U.S. patent application number 16/503411 was filed with the patent office on 2019-10-24 for systems and methods for analyzing snapshots.
The applicant listed for this patent is Commvault Systems, Inc.. Invention is credited to David Ngo.
Application Number | 20190324860 16/503411 |
Document ID | / |
Family ID | 44188688 |
Filed Date | 2019-10-24 |
![](/patent/app/20190324860/US20190324860A1-20191024-D00000.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00001.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00002.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00003.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00004.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00005.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00006.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00007.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00008.png)
![](/patent/app/20190324860/US20190324860A1-20191024-D00009.png)
United States Patent
Application |
20190324860 |
Kind Code |
A1 |
Ngo; David |
October 24, 2019 |
SYSTEMS AND METHODS FOR ANALYZING SNAPSHOTS
Abstract
This application describes techniques for creating a second
snapshot of a first snapshot of a set of data, modifying the first
snapshot, and reverting the modifications to the first snapshot.
For example, portions of one or more transaction logs may be played
into a database to put the database in a particular state a
particular point in time. The second snapshot may then be used to
revert to a prior state of the database such that additional
transaction logs may be played into the database. These techniques
enable the ability to put the database into multiple states as the
database existed at multiple points in time. Therefore, data can be
recovered from the database as the data existed at different points
in time. Moreover, individual data objects in the database can be
accessed and analyzed as the individual data objects existed at
different points in time.
Inventors: |
Ngo; David; (Shrewsbury,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Commvault Systems, Inc. |
Tinton Falls |
NJ |
US |
|
|
Family ID: |
44188688 |
Appl. No.: |
16/503411 |
Filed: |
July 3, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15069228 |
Mar 14, 2016 |
10379957 |
|
|
16503411 |
|
|
|
|
13874323 |
Apr 30, 2013 |
9298559 |
|
|
15069228 |
|
|
|
|
12978984 |
Dec 27, 2010 |
8433682 |
|
|
13874323 |
|
|
|
|
61291805 |
Dec 31, 2009 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F 11/1461 20130101;
G06F 11/1471 20130101; G06F 2201/84 20130101; G06F 11/1446
20130101; G06F 16/2477 20190101; G06F 2201/80 20130101; G06F
11/1448 20130101 |
International
Class: |
G06F 11/14 20060101
G06F011/14; G06F 16/2458 20060101 G06F016/2458 |
Claims
1. At least one non-transitory, computer-readable medium carrying
instructions, which when executed by at least one data processing
device, executes operations for analyzing a snapshot of a set of
data, the operations comprising: causing to be generated, by the
least one data processing device, a first snapshot of a set of data
at a first time, wherein the first snapshot captures a first state
of the set of data at the first time, and wherein the set of data
includes multiple data objects; causing to be generated a second
snapshot at a second, later time, wherein the second snapshot
captures a second state of the set of data at the second time;
causing to be generated, before an accessing of the at least one of
the multiple data objects, a snapshot of the second snapshot and at
least one associated transaction log; and permitting to be
accessed, via the first snapshot, at least one of the multiple data
objects.
2. The tangible computer-readable medium of claim 1, further
comprising causing a reversion to the second state of the set of
data.
3. The tangible computer-readable medium of claim 1, wherein the
second snapshot includes a copy of logical associations for the
first snapshot.
4. The tangible computer-readable medium of claim 1, further
comprising modifying the first snapshot after the second snapshot
is generated.
5. The tangible computer-readable medium of claim 1, wherein
causing the first snapshot of the set of data to be generated
includes causing to be generated the first snapshot of the set of
data at least partly with a software-based snapshot provider.
6. The tangible computer-readable medium of claim 1, wherein
causing the first snapshot of the set of data to be generated
includes causing to be generated the first snapshot of the set of
data at least partly with a hardware-based snapshot provider.
7. The tangible computer-readable medium of claim 1, wherein the
set of data includes a database and database logs, and the method
further comprises modifying the first snapshot by playing one or
more database logs into the database.
8. The tangible computer-readable medium of claim 1, further
comprising reverting to the second state of the set of data by
performing a revert operation utilizing the snapshot of the second
snapshot.
9. The tangible computer-readable medium of claim 1, wherein the
set of data is utilized by an application, and wherein the
application includes either an email server, a Structured Query
Language (SQL) server, a file server, or an application server.
10. The tangible computer-readable medium of claim 1, further
comprising, modifying the first snapshot, and after reverting to
the second state of the set of data, modifying the first snapshot
again.
11. The tangible computer-readable medium of claim 1, further
comprising causing at least one operation on the accessed one or
more multiple data objects to be performed, wherein the at least
one operation includes-- indexing the multiple data objects and
adding information to an index, or associating the multiple data
objects with one or more classifications and storing the one or
more classifications in a metabase, or extracting the multiple data
objects from the set of data and copying the multiple data objects
to a storage device.
12. At least one non-transitory, computer-readable medium carrying
instructions, which when executed by at least one computing device,
performs operations for analyzing data, the operations comprising:
receiving at least one replication log indicating at least one
change to a first data set, wherein the first data set includes one
or more individual data objects, wherein the least one replication
log can be utilized to implement the at least one change to a
second data set as the first data set existed at a first point in
time, and wherein the least one replication log or data associated
therewith includes at least one indication of a second point in
time at which the first data set is consistent; utilizing, by the
computing device, the least one replication log to cause the at
least one change to the second data to be generated; causing to be
created a snapshot of the second data at or near the second point
in time; analyzing the snapshot of the second data changed
according to the least one replication log; and accessing the one
or more of the individual data objects as the data objects existed
at the second point in time.
13. The at least one computer-readable medium of claim 12 wherein
the second data includes a database and at least one database log,
wherein the least one replication log includes modifications to the
database and/or the at least one database log, and wherein
utilizing the least one replication log to replicate the changes to
the second data includes modifying the database using the at least
one database log.
14. The at least one computer-readable medium of claim 12 wherein
analyzing the snapshot of the second data includes performing at
least one modification to the snapshot of the second data, and the
method further comprises: after analyzing the snapshot of the
second data, reverting the snapshot of the second data; and after
reverting the snapshot of the second data, utilizing least one
replication log to replicate additional changes to the second
data.
15. The at least one computer-readable medium of claim 12 wherein
the first data set includes a database, and wherein the method
further comprises creating a first snapshot of both the database
and transaction or replication logs associated with the database,
playing portions of one or more of the logs to commit corresponding
changes to the database, and creating a second snapshot of the
first snapshot, wherein a user can analyze data in the database as
the database existed as of a time that the logs were played into
the database.
16. The at least one computer-readable medium of claim 12, wherein
the method further comprises: causing an initial full second data
to be created, thereafter causing a snapshot of the first data set
to be created, and thereafter, causing incremental copies or
snapshots of the first data set and the logs to be created.
17. The at least one computer-readable medium of claim 12, wherein
the method further comprises performing at least one test of the
first snapshot in order to validate or verify the snapshot and
ensure that the first data set was correctly copied.
18. At least one non-transitory, computer-readable medium carrying
instructions, which when executed by at least one computing device,
performs operations for modifying data, the operations comprising:
creating a second snapshot of a first snapshot of a set of data,
wherein the set of data is for a database; modifying the first
snapshot; and reverting the modifications to the first snapshot,
wherein the reverting includes employ portions of one or more
transaction logs to revert the set of data for the database to a
first state corresponding to a first point in time for the first
snapshot, and wherein the second snapshot is configured to revert
the set of data for the database to a second state by employing
portions of one or more additional transaction logs, so that the
operations enable the set of data for the database to be put into
multiple states corresponding to when the database existed at
multiple points in time and allowing recovery of data from the
database as the data existed at different points in time.
19. The at least one computer-readable medium of claim 18, wherein
the first snapshot is a snapshot of both the set of data for the
database and transaction logs associated with the database, wherein
the portions of one or more transaction logs are usable to commit
corresponding changes to the database.
20. The at least one computer-readable medium of claim 18, wherein
the first snapshot is a snapshot of both the set of data for the
database and transaction logs associated with the database, wherein
the portions of one or more transaction logs are usable to commit
corresponding changes to the database.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/069,228, filed Mar. 14, 2016, which is a
continuation of U.S. patent application Ser. No. 13/874,323,
entitled "SYSTEMS AND METHODS FOR ANALYZING SNAPSHOTS," filed Apr.
30, 2013, now U.S. Pat. No. 9,298,559, which is a continuation of
U.S. patent application Ser. No. 12/978,984, entitled "SYSTEMS AND
METHODS FOR ANALYZING SNAPSHOTS," filed Dec. 27, 2010, now U.S.
Pat. No. 8,433,682, which claims priority to and the benefit of
U.S. Patent Application No. 61/291,805, entitled "SYSTEMS AND
METHODS FOR ANALYZING SNAPSHOTS," filed on Dec. 31, 2009, and is
related to U.S. patent application Ser. No. 12/558,947, entitled
"USING A SNAPSHOT AS A DATA SOURCE," filed on Sep. 14, 2009 and
U.S. patent application Ser. No. 12/979,101 filed on Dec. 27, 2010,
entitled "SYSTEMS AND METHODS FOR PERFORMING DATA MANAGEMENT
OPERATIONS USING SNAPSHOTS," each of which is incorporated by
reference in its entirety.
BACKGROUND
[0002] A transactional database application, such as Microsoft SQL
Server or Microsoft Exchange Server, typically writes transactions
to transaction logs prior to committing the transactions to the
database. The database application then commits the transactions in
the transaction logs to the database as permitted.
[0003] An administrator typically protects the data of the
transactional database application by directing data protection
software to periodically perform a full backup (or other data
protection operation) of the database and the transaction logs, as
well as additional incremental backups (or other data protection
operations) to capture changed data. For example, the administrator
may direct the software to perform a full snapshot copy of the
database and the transaction logs. The administrator may then
direct the software to perform additional snapshots of the database
and the transaction logs to capture data that has changed, such as
additional transaction logs, since the full snapshot copy was
performed.
[0004] In order to recover the transactional database application
as it existed at a specific point in time, the administrator
typically directs the software to recover the database and then
"play" the necessary transaction logs. Playing (alternatively
referred to as replaying or applying) transaction logs refers to
committing transactions in the transaction logs to the database.
This brings the transactional database application to the state it
was in at the specific point in time. However, once the
administrator has recovered the transactional database application,
the administrator is typically not able to play additional
transaction logs to bring the transactional database application to
a state at a later point in time. Stated another way, once a
database is put into a state corresponding to a particular point in
time in order to recover data from the database as the data existed
at that particular point in time, the administrator cannot put the
database into another state corresponding to another point in time
in order to recover data from the database as the data existed at
the other point in time.
[0005] The need exists for a system that overcomes the above
problems, as well as one that provides additional benefits.
Overall, the examples herein of some prior or related systems and
their associated limitations are intended to be illustrative and
not exclusive. Other limitations of existing or prior systems will
become apparent to those of skill in the art upon reading the
following Detailed Description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a block diagram illustrating an example of a data
storage enterprise that may employ aspects of the invention.
[0007] FIG. 2 is a block diagram illustrating in more detail
certain components of a data storage system according to some
examples.
[0008] FIG. 3 is a flow diagram of a process for analyzing a
snapshot.
[0009] FIGS. 4A-4E are diagrams illustrating aspects of the process
of FIG. 3.
[0010] FIG. 5 is a flow diagram of another process for analyzing a
snapshot.
DETAILED DESCRIPTION
[0011] The headings provided herein are for convenience only and do
not necessarily affect the scope or meaning of the claimed
invention.
Overview
[0012] This application describes, among other things, techniques
for creating a second snapshot of a first snapshot of a set of
data, modifying the first snapshot, and reverting the modifications
to the first snapshot. For example, the described techniques may be
used to play portions of one or more transaction logs into a
database to put the database in a particular state that corresponds
to a particular point in time. The second snapshot may then be used
to revert the database to a prior state such that additional
transaction logs may be played into the database. These techniques
enable the database to be put into multiple states that correspond
to when the database existed at multiple points in time. Therefore,
data can be recovered from the database as the data existed at
different points in time. Moreover, individual data objects in the
database can be accessed and analyzed as the individual data
objects existed at different points in time.
[0013] In some examples, these techniques described herein involve
creating a first snapshot of both a database and transaction logs
associated with the database. Portions of one or more transaction
logs may be played to commit corresponding changes to the database.
A second snapshot is then taken of the first snapshot. The database
can then be analyzed as it existed as of the time that the
transaction logs were played into the database. Using the example
of a Microsoft Exchange database, the database can be analyzed to
read data from individual mailboxes, emails, attachments, etc. The
second snapshot is then used to revert the database to the state it
existed in as of the time the second snapshot was taken. Any number
of transaction logs can then be played in order to put the database
in a state that the database existed in at multiple points in
time.
[0014] In some examples, the techniques described herein involve
utilizing replication logs to take snapshots of a replication copy
of data. The replication logs indicate changes to a first set of
data, and can be used to replicate the changes to a second set of
data that is a copy of the first set of data as the first set of
data existed at a first point in time. The replication logs include
at least one marker indicating a second point in time at which the
first set of data is consistent. At least some of the replication
logs are utilized to replicate at least some of the changes to the
second set of data. Upon reaching the marker in the replication
logs, a snapshot of the second set of data is created. The snapshot
of the second set of data is analyzed, which may include accessing
individual data objects within the second set of data.
[0015] Various examples of the invention will now be described. The
following description provides specific details for a thorough
understanding and enabling description of these examples. One
skilled in the relevant art will understand, however, that the
invention may be practiced without many of these details. Likewise,
one skilled in the relevant art will also understand that the
invention may include many other obvious features not described in
detail herein. Additionally, some well-known structures or
functions may not be shown or described in detail below, so as to
avoid unnecessarily obscuring the relevant description.
[0016] The terminology used below is to be interpreted in its
broadest reasonable manner, even though it is being used in
conjunction with a detailed description of certain specific
examples of the invention. Indeed, certain terms may even be
emphasized below; however, any terminology intended to be
interpreted in any restricted manner will be overtly and
specifically defined as such in this Detailed Description
section.
[0017] FIGS. 1 and 2 and the discussion herein provide a brief,
general description of suitable specialized environments in which
aspects of the invention can be implemented. Those skilled in the
relevant art will appreciate that aspects of the invention can be
practiced with other communications, data processing, or computer
system configurations, including: Internet appliances, hand-held
devices (including personal digital assistants (PDAs)), wearable
computers, all manner of cellular phones, mobile phones, and/or
mobile devices, multi-processor systems, microprocessor-based or
programmable consumer electronics, set-top boxes, network PCs,
mini-computers, mainframe computers, and the like. The terms
"computer," "server," "host," "host system," "client," and the like
are generally used interchangeably herein, and refer to any of the
above devices and systems, as well as any data processor.
[0018] While aspects of the invention, such as certain functions,
are described as being performed exclusively on a single device,
the invention can also be practiced in distributed environments
where functions or modules are shared among disparate processing
devices, which are linked through a communications network, such as
a Local Area Network (LAN), Wide Area Network (WAN), and/or the
Internet. In a distributed computing environment, program modules
may be located in both local and remote memory storage devices.
[0019] Aspects of the invention may be stored or distributed on
computer-readable media, including tangible computer-readable
storage media such as magnetically or optically readable computer
discs, hard-wired or preprogrammed chips (e.g., EEPROM
semiconductor chips), nanotechnology memory, biological memory, or
other data storage media. Alternatively, computer implemented
instructions, data structures, screen displays, and other data
under aspects of the invention may be distributed over the Internet
or over other networks (including wireless networks), on a
propagated signal on a propagation medium (e.g., an electromagnetic
wave(s), a sound wave, etc.) over a period of time, or they may be
provided on any analog or digital network (packet switched, circuit
switched, or other scheme).
[0020] Aspects of the invention will now be described in detail
with respect to FIGS. 1 through 4. FIG. 1 illustrates an example of
a data storage system that may employ aspects of the invention.
FIG. 2 illustrates in more detail certain components of the example
data storage system of FIG. 1. FIG. 3 illustrates a process for
creating a second snapshot of a first snapshot of a set of data,
such as a database and associated logs. FIGS. 4A-4E illustrate
aspects of the process of FIG. 3 in more detail. FIG. 5 illustrates
a process for utilizing consistency points to take snapshots of a
set of data, such as a database and associated logs, in a data
replication process.
Suitable Data Storage System
[0021] FIG. 1 illustrates an example of one arrangement of
resources in a computing network, comprising a data storage system
150. The resources in the data storage system 150 may employ the
processes and techniques described herein. The system 150 includes
a storage manager 105, one or more data agents 195, one or more
secondary storage computing devices 165, one or more storage
devices 115, one or more computing devices 130 (called clients
130), one or more data or information stores 160 and 162, and a
single instancing database 123. The storage manager 105 includes an
index 111, a jobs agent 120, an interface agent 125, and a
management agent 131. The system 150 may represent a modular
storage system such as the CommVault QiNetix system, and also the
CommVault GALAXY backup system, available from CommVault Systems,
Inc. of Oceanport, N.J., aspects of which are further described in
the commonly-assigned U.S. patent application Ser. No. 09/610,738,
now U.S. Pat. No. 7,035,880, the entirety of which is incorporated
by reference herein. The system 150 may also represent a modular
storage system such as the CommVault Simpana system, also available
from CommVault Systems, Inc.
[0022] The system 150 may generally include combinations of
hardware and software components associated with performing storage
operations on electronic data. Storage operations include copying,
backing up, creating, storing, retrieving, and/or migrating primary
storage data (e.g., data stores 160 and/or 162) and secondary
storage data (which may include, for example, snapshot copies,
backup copies, hierarchical storage management (HSM) copies,
archive copies, and other types of copies of electronic data stored
on storage devices 115). The system 150 may provide one or more
integrated management consoles for users or system processes to
interface with in order to perform certain storage operations on
electronic data as further described herein. Such integrated
management consoles may be displayed at a central control facility
or several similar consoles distributed throughout multiple network
locations to provide global or geographically specific network data
storage information.
[0023] In one example, storage operations may be performed
according to various storage preferences, for example, as expressed
by a user preference, a storage policy, a schedule policy, and/or a
retention policy. A "storage policy" is generally a data structure
or other information source that includes a set of preferences and
other storage criteria associated with performing a storage
operation. The preferences and storage criteria may include, but
are not limited to, a storage location, relationships between
system components, network pathways to utilize in a storage
operation, data characteristics, compression or encryption
requirements, preferred system components to utilize in a storage
operation, a single instancing or variable instancing policy to
apply to the data, and/or other criteria relating to a storage
operation. For example, a storage policy may indicate that certain
data is to be stored in the storage device 115, retained for a
specified period of time before being aged to another tier of
secondary storage, copied to the storage device 115 using a
specified number of data streams, etc.
[0024] A "schedule policy" may specify a frequency with which to
perform storage operations and a window of time within which to
perform them. For example, a schedule policy may specify that a
storage operation is to be performed every Saturday morning from
2:00 a.m. to 4:00 a.m. A "retention policy" may specify how long
data is to be retained at specific tiers of storage or what
criteria must be met before data may be pruned or moved from one
tier of storage to another tier of storage. In some cases, the
storage policy includes information generally specified by the
schedule policy and/or the retention policy. (Put another way, the
storage policy includes the schedule policy and/or the retention
policy.) Storage policies, schedule policies and/or retention
policies may be stored in a database of the storage manager 105, to
archive media as metadata for use in restore operations or other
storage operations, or to other locations or components of the
system 150.
[0025] The system 150 may comprise a storage operation cell that is
one of multiple storage operation cells arranged in a hierarchy or
other organization. Storage operation cells may be related to
backup cells and provide some or all of the functionality of backup
cells as described in the assignee's U.S. patent application Ser.
No. 09/354,058, now U.S. Pat. No. 7,395,282, which is incorporated
herein by reference in its entirety. However, storage operation
cells may also perform additional types of storage operations and
other types of storage management functions that are not generally
offered by backup cells.
[0026] Storage operation cells may contain not only physical
devices, but also may represent logical concepts, organizations,
and hierarchies. For example, a first storage operation cell may be
configured to perform a first type of storage operations such as
HSM operations, which may include backup or other types of data
migration, and may include a variety of physical components
including a storage manager 105 (or management agent 131), a
secondary storage computing device 165, a client 130, and other
components as described herein. A second storage operation cell may
contain the same or similar physical components; however, it may be
configured to perform a second type of storage operations, such as
storage resource management (SRM) operations, and may include
monitoring a primary data copy or performing other known SRM
operations.
[0027] Thus, as can be seen from the above, although the first and
second storage operation cells are logically distinct entities
configured to perform different management functions (i.e., HSM and
SRM, respectively), each storage operation cell may contain the
same or similar physical devices. Alternatively, different storage
operation cells may contain some of the same physical devices and
not others. For example, a storage operation cell configured to
perform SRM tasks may contain a secondary storage computing device
165, client 130, or other network device connected to a primary
storage volume, while a storage operation cell configured to
perform HSM tasks may instead include a secondary storage computing
device 165, client 130, or other network device connected to a
secondary storage volume and not contain the elements or components
associated with and including the primary storage volume. (The term
"connected" as used herein does not necessarily require a physical
connection; rather, it could refer to two devices that are operably
coupled to each other, communicably coupled to each other, in
communication with each other, or more generally, refer to the
capability of two devices to communicate with each other.) These
two storage operation cells, however, may each include a different
storage manager 105 that coordinates storage operations via the
same secondary storage computing devices 165 and storage devices
115. This "overlapping" configuration allows storage resources to
be accessed by more than one storage manager 105, such that
multiple paths exist to each storage device 115 facilitating
failover, load balancing, and promoting robust data access via
alternative routes.
[0028] Alternatively or additionally, the same storage manager 105
may control two or more storage operation cells (whether or not
each storage operation cell has its own dedicated storage manager
105). Moreover, in certain embodiments, the extent or type of
overlap may be user-defined (through a control console) or may be
automatically configured to optimize data storage and/or
retrieval.
[0029] The clients 130 typically include application software for
performing various operations. Clients 130 typically also include
an operating system on which the application software runs. A file
system can be provided to facilitate and control file access by the
operating system and application software. File systems can
facilitate access to local and remote storage devices for file or
data access and storage. Clients 130 can also include local storage
such as a media module media drive with fixed or removable
media.
[0030] In some examples, the clients 130 include storage mechanisms
for allowing computer programs or other instructions or data to be
loaded into memory for execution. Such storage mechanisms might
include, for example, a fixed or removable storage unit and an
interface. Examples of such storage units and interfaces can
include a program cartridge and cartridge interface, a removable
memory (for example, a flash memory or other removable memory
module) and memory slot, a PCMCIA slot and card, and other fixed or
removable storage units and interfaces that allow software and data
to be transferred from the storage unit to memory.
[0031] Data agent 195 may be a software module or part of a
software module that is generally responsible for performing
storage operations on the data of the client 130 stored in data
store 160/162 or other memory location. Each client 130 may have at
least one data agent 195 and the system 150 can support multiple
clients 130. Data agent 195 may be distributed between client 130
and storage manager 105 (and any other intermediate components), or
it may be deployed from a remote location or its functions
approximated by a remote process that performs some or all of the
functions of data agent 195.
[0032] As used herein, the term module might describe a given unit
of functionality that can be performed in accordance with one or
more embodiments of the present invention. As used herein, a module
might be implemented utilizing any form of hardware, software,
firmware, or a combination thereof. For example, one or more
processors, controllers, ASICs, PLAs, logical components, software
routines or other mechanisms might be implemented to make up a
module. In implementation, the various modules described herein
might be implemented as discrete modules or the functions and
features described can be shared in part or in total among one or
more modules. In other words, as would be apparent to one of
ordinary skill in the art after reading this description, the
various features and functionality described herein may be
implemented in any given application and can be implemented in one
or more separate or shared modules in various combinations and
permutations. Even though various features or elements of
functionality may be individually described or claimed as separate
modules, one of ordinary skill in the art will understand that
these features and functionality can be shared among one or more
common software and hardware elements, and such description shall
not require or imply that separate hardware or software components
are used to implement such features or functionality.
[0033] The overall system 150 may employ multiple data agents 195,
each of which may perform storage operations on data associated
with a different application. For example, different individual
data agents 195 may be designed to handle Microsoft Exchange data,
Lotus Notes data, Microsoft Windows file system data, Microsoft
Active Directory Objects data, Microsoft SQL Server data, Microsoft
Sharepoint Server data, and other types of data known in the art.
Other embodiments may employ one or more generic data agents 195
that can handle and process multiple data types rather than using
the specialized data agents described above.
[0034] If a client 130 has two or more types of data, one data
agent 195 may be required for each data type to perform storage
operations on the data of the client 130. For example, to back up,
migrate, and restore all the data on a Microsoft Exchange server,
the client 130 may use one Microsoft Exchange Mailbox data agent
195 to back up the Exchange mailboxes, one Microsoft Exchange
Database data agent 195 to back up the Exchange databases, one
Microsoft Exchange Public Folder data agent 195 to back up the
Exchange Public Folders, and one Microsoft Windows File System data
agent 195 to back up the file system of the client 130. These data
agents 195 would be treated as four separate data agents 195 by the
system even though they reside on the same client 130.
[0035] Alternatively, the overall system 150 may use one or more
generic data agents 195, each of which may be capable of handling
two or more data types. For example, one generic data agent 195 may
be used to back up, migrate and restore Microsoft Exchange Mailbox
data and Microsoft Exchange Database data while another generic
data agent 195 may handle Microsoft Exchange Public Folder data and
Microsoft Windows File System data, etc.
[0036] Data agents 195 may be responsible for arranging or packing
data to be copied or migrated into a certain format such as an
archive file. Nonetheless, it will be understood that this
represents only one example, and any suitable packing or
containerization technique or transfer methodology may be used if
desired. Such an archive file may include metadata, a list of files
or data objects copied, the file, and data objects themselves.
Moreover, any data moved by the data agents may be tracked within
the system by updating indexes associated with appropriate storage
managers 105 or secondary storage computing devices 165. As used
herein, a file or a data object refers to any collection or
grouping of bytes of data that can be viewed as one or more logical
units.
[0037] Generally speaking, storage manager 105 may be a software
module or other application that coordinates and controls storage
operations performed by the system 150. Storage manager 105 may
communicate with some or all elements of the system 150, including
clients 130, data agents 195, secondary storage computing devices
165, and storage devices 115, to initiate and manage storage
operations (e.g., backups, migrations, data recovery operations,
etc.).
[0038] Storage manager 105 may include a jobs agent 120 that
monitors the status of some or all storage operations previously
performed, currently being performed, or scheduled to be performed
by the system 150. (One or more storage operations are
alternatively referred to herein as a "job" or "jobs.") Jobs agent
120 may be communicatively coupled to an interface agent 125 (e.g.,
a software module or application). Interface agent 125 may include
information processing and display software, such as a graphical
user interface ("GUI"), an application programming interface
("API"), or other interactive interface through which users and
system processes can retrieve information about the status of
storage operations. For example, in an arrangement of multiple
storage operations cell, through interface agent 125, users may
optionally issue instructions to various storage operation cells
regarding performance of the storage operations as described and
contemplated herein. For example, a user may modify a schedule
concerning the number of pending snapshot copies or other types of
copies scheduled as needed to suit particular needs or
requirements. As another example, a user may employ the GUI to view
the status of pending storage operations in some or all of the
storage operation cells in a given network or to monitor the status
of certain components in a particular storage operation cell (e.g.,
the amount of storage capacity left in a particular storage device
115).
[0039] Storage manager 105 may also include a management agent 131
that is typically implemented as a software module or application
program. In general, management agent 131 provides an interface
that allows various management agents 131 in other storage
operation cells to communicate with one another. For example,
assume a certain network configuration includes multiple storage
operation cells hierarchically arranged or otherwise logically
related in a WAN or LAN configuration. With this arrangement, each
storage operation cell may be connected to the other through each
respective interface agent 125. This allows each storage operation
cell to send and receive certain pertinent information from other
storage operation cells, including status information, routing
information, information regarding capacity and utilization, etc.
These communications paths may also be used to convey information
and instructions regarding storage operations.
[0040] For example, a management agent 131 in a first storage
operation cell may communicate with a management agent 131 in a
second storage operation cell regarding the status of storage
operations in the second storage operation cell. Another
illustrative example includes the case where a management agent 131
in a first storage operation cell communicates with a management
agent 131 in a second storage operation cell to control storage
manager 105 (and other components) of the second storage operation
cell via management agent 131 contained in storage manager 105.
[0041] Another illustrative example is the case where management
agent 131 in a first storage operation cell communicates directly
with and controls the components in a second storage operation cell
and bypasses the storage manager 105 in the second storage
operation cell. If desired, storage operation cells can also be
organized hierarchically such that hierarchically superior cells
control or pass information to hierarchically subordinate cells or
vice versa.
[0042] Storage manager 105 may also maintain an index, a database,
or other data structure 111. The data stored in database 111 may be
used to indicate logical associations between components of the
system, user preferences, management tasks, media containerization
and data storage information or other useful data. For example, the
storage manager 105 may use data from database 111 to track logical
associations between secondary storage computing device 165 and
storage devices 115 (or movement of data as containerized from
primary to secondary storage).
[0043] Generally speaking, the secondary storage computing device
165, which may also be referred to as a media agent, may be
implemented as a software module that conveys data, as directed by
storage manager 105, between a client 130 and one or more storage
devices 115 such as a tape library, a magnetic media storage
device, an optical media storage device, or any other suitable
storage device. In one embodiment, secondary storage computing
device 165 may be communicatively coupled to and control a storage
device 115. A secondary storage computing device 165 may be
considered to be associated with a particular storage device 115 if
that secondary storage computing device 165 is capable of routing
and storing data to that particular storage device 115.
[0044] In operation, a secondary storage computing device 165
associated with a particular storage device 115 may instruct the
storage device to use a robotic arm or other retrieval means to
load or eject a certain storage media, and to subsequently archive,
migrate, or restore data to or from that media. Secondary storage
computing device 165 may communicate with a storage device 115 via
a suitable communications path such as a SCSI or Fibre Channel
communications link. In some embodiments, the storage device 115
may be communicatively coupled to the storage manager 105 via a
SAN.
[0045] Each secondary storage computing device 165 may maintain an
index, a database, or other data structure 161 that may store index
data generated during storage operations for secondary storage (SS)
as described herein, including creating a metabase (MB). For
example, performing storage operations on Microsoft Exchange data
may generate index data. Such index data provides a secondary
storage computing device 165 or other external device with a fast
and efficient mechanism for locating data stored or backed up.
Thus, a secondary storage computing device index 161, or a database
111 of a storage manager 105, may store data associating a client
130 with a particular secondary storage computing device 165 or
storage device 115, for example, as specified in a storage policy,
while a database or other data structure in secondary storage
computing device 165 may indicate where specifically the data of
the client 130 is stored in storage device 115, what specific files
were stored, and other information associated with storage of the
data of the client 130. In some embodiments, such index data may be
stored along with the data backed up in a storage device 115, with
an additional copy of the index data written to index cache in a
secondary storage device. Thus the data is readily available for
use in storage operations and other activities without having to be
first retrieved from the storage device 115.
[0046] Generally speaking, information stored in cache is typically
recent information that reflects certain particulars about
operations that have recently occurred. After a certain period of
time, this information is sent to secondary storage and tracked.
This information may need to be retrieved and uploaded back into a
cache or other memory in a secondary computing device before data
can be retrieved from storage device 115. In some embodiments, the
cached information may include information regarding format or
containerization of archives or other files stored on storage
device 115.
[0047] One or more of the secondary storage computing devices 165
may also maintain one or more single instance databases 123. Single
instancing (alternatively called data deduplication) generally
refers to storing in secondary storage only a single instance of
each data object (or data block) in a set of data (e.g., primary
data). More details as to single instancing may be found in one or
more of the following commonly-assigned U.S. patent applications:
1) U.S. patent application Ser. No. 11/269,512 (entitled SYSTEM AND
METHOD TO SUPPORT SINGLE INSTANCE STORAGE OPERATIONS, Attorney
Docket No. 60692-8023.US00); 2) U.S. patent application Ser. No.
12/145,347 (entitled APPLICATION-AWARE AND REMOTE SINGLE INSTANCE
DATA MANAGEMENT, Attorney Docket No. 60692-8056.US00); or 3) U.S.
patent application Ser. No. 12/145,342 (entitled APPLICATION-AWARE
AND REMOTE SINGLE INSTANCE DATA MANAGEMENT, Attorney Docket No.
60692-8057.US00), 4) U.S. patent application Ser. No. 11/963,623
(entitled SYSTEM AND METHOD FOR STORING REDUNDANT INFORMATION,
Attorney Docket No. 60692-8036.US02); 5) U.S. patent application
Ser. No. 11/950,376 (entitled SYSTEMS AND METHODS FOR CREATING
COPIES OF DATA SUCH AS ARCHIVE COPIES, Attorney Docket No.
60692-8037.US01); 6) U.S. patent application Ser. No. 12/565,576
(entitled SYSTEMS AND METHODS FOR MANAGING SINGLE INSTANCING DATA,
Attorney Docket No. 60692-8067.US01); or 7) U.S. patent application
Ser. No. 12/647,906 (entitled BLOCK-LEVEL SINGLE INSTANCING,
Attorney Docket No. 60692-8073.US01), each of which is incorporated
by reference herein in its entirety.
[0048] In some examples, the secondary storage computing devices
165 maintain one or more variable instance databases. Variable
instancing generally refers to storing in secondary storage one or
more instances, but fewer than the total number of instances, of
each data block (or data object) in a set of data (e.g., primary
data). More details as to variable instancing may be found in the
commonly-assigned U.S. patent application Ser. No. 12/649,454
(entitled STORING A VARIABLE NUMBER OF INSTANCES OF DATA OBJECTS,
Attorney Docket No. 60692-8068.US01).
[0049] In some embodiments, certain components may reside and
execute on the same computer. For example, in some embodiments, a
client 130 such as a data agent 195, or a storage manager 105,
coordinates and directs local archiving, migration, and retrieval
application functions as further described in the
previously-referenced U.S. patent application Ser. No. 09/610,738.
This client 130 can function independently or together with other
similar clients 130.
[0050] As shown in FIG. 1, each secondary storage computing device
165 has its own associated metabase 161. Each client 130 may also
have its own associated metabase 170. However in some embodiments,
each "tier" of storage, such as primary storage, secondary storage,
tertiary storage, etc., may have multiple metabases or a
centralized metabase, as described herein. For example, rather than
a separate metabase or index associated with each client 130 in
FIG. 1, the metabases on this storage tier may be centralized.
Similarly, second and other tiers of storage may have either
centralized or distributed metabases. Moreover, mixed architecture
systems may be used if desired, that may include a first tier
centralized metabase system coupled to a second tier storage system
having distributed metabases and vice versa, etc.
[0051] Moreover, in operation, a storage manager 105 or other
management module may keep track of certain information that allows
the storage manager 105 to select, designate, or otherwise identify
metabases to be searched in response to certain queries as further
described herein. Movement of data between primary and secondary
storage may also involve movement of associated metadata and other
tracking information as further described herein.
[0052] In some examples, primary data may be organized into one or
more sub-clients. A sub-client is a portion of the data of one or
more clients 130, and can contain either all of the data of the
clients 130 or a designated subset thereof. As depicted in FIG. 1,
the data store 162 includes two sub-clients. For example, an
administrator (or other user with the appropriate permissions; the
term administrator is used herein for brevity) may find it
preferable to separate email data from financial data using two
different sub-clients having different storage preferences,
retention criteria, etc.
Suitable System for Creating Snapshots
[0053] FIG. 2 is a block diagram illustrating in more detail
certain components 200 of the data storage system 150 of FIG. 1.
FIG. 2 depicts one of the clients 130, secondary storage computing
device 165, secondary storage computing device index 161, and
storage device 115.
[0054] In addition to the data agent 195, the client 130 includes a
snapshot component 205, an application 210, and data 215. The
application 210 may be any application executing on the client 130,
such as a database server application (for example, Microsoft SQL
server, Microsoft Active Directory Server, Oracle, etc.), an email
server application (for example, Microsoft Exchange Server, Apache,
etc.), or other types of servers (for example, application servers
such as Microsoft SharePoint servers or web servers, virtual
machine servers such as Microsoft Virtual Server, file servers,
etc.). The application 210 has associated data 215, which includes
a database 220 and logs 225, shown as logs one through n. The
application 210 may write data to the database 220 using
transactional techniques. That is, the application 210 may write
changes to the logs 225 before committing the changes to the
database 220.
[0055] For example, consider an application 210 that is an email
server application 210, such as Microsoft Exchange. The email
server application 210 has an associated database 220 to which it
writes its data in a transactional manner. The data 215 of the
application also includes logs 225. For example, logs one and two
may exist as of day one. A full copy of the database 220 and its
logs 225 that occurs on day one may result in copying the database
220 and logs one and two. On day two, the email server application
210 creates logs three and four, and an incremental copy of the
database 220 and its logs 225 on day two would only copy logs three
and four. On day three, logs five and six are created, and an
incremental copy of the database 220 and its logs 225 on day three
would copy over logs five and six. Accordingly, the state of the
data 215 of the email server application 210 can be recovered to
multiple points in time over days one through three, by playing
portions of the appropriate logs 225 into the database 220. Further
incremental copies of additional logs 220 can be made at later
points in time. Although this example describes that the email
server application 210 creates two logs 225 each day, those of
skill in the art will understand that any number of logs (i.e.,
zero logs, one log, or greater than two logs) may be created each
day.
[0056] The snapshot component 205 creates snapshots of the data 215
of the client 130. The snapshot component 205 includes software
components and may also include hardware and/or firmware
components. The snapshot component 205 may be provided in its
entirety by a single entity (for example, a single vendor), or the
snapshot component 205 may include sub-components that are provided
by different entities (such as multiple vendors).
[0057] In some examples, the snapshot component includes a
Microsoft Volume Shadow Copy Service (VSS) sub-component and a
software-based VSS provider sub-component that is provided by the
assignee of the present application, CommVault Systems, Inc. In
these examples, the data agent 195 interacts with the Microsoft VSS
sub-component to create snapshots. The Microsoft VSS sub-component
notifies the application 210 to prepare the data 215 for creating a
snapshot. The application 210 prepares the data 215 in an
appropriate manner (such as completing open transactions, flushing
application caches, etc.). The Microsoft VSS sub-component
initiates a commit phase and notifies the application 210 that the
application 210 should be quiesced and to freeze writes to the data
215. The Microsoft VSS sub-component may also flush a file system
buffer and freeze the file system to ensure that file system
metadata is written and that the data 215 is written in a
consistent order. The Microsoft VSS sub-component notifies the VSS
provider sub-component to create the snapshot, and the VSS provider
sub-component creates the snapshot. The Microsoft VSS sub-component
then "thaws" or resumes file system operations and notifies the
application 210 that the application 210 can unquiesce and complete
any writes to the data 215.
[0058] In other examples, in addition to or as an alternative to
the software-based VSS provider sub-component, the snapshot
component 205 includes other software-based VSS provider
sub-components, such as a Microsoft system software provider, a
Microsoft Data Protection Manager provider sub-component or a
NetApp SnapManager provider sub-component. These other
software-based VSS provider sub-components may create snapshots in
manners similar to the manner described in the preceding paragraph,
or may use other techniques to create snapshots.
[0059] In other examples, in addition to the Microsoft VSS
sub-component, the snapshot component 205 includes one or more
hardware-based VSS provider sub-components, such as those provided
by vendors such as Hewlett-Packard, EMC, NetApp, IBM, and other
vendors. These hardware-based VSS provider sub-components may
create snapshots in manners similar to the manner described above,
or may use other techniques to create snapshots. Those of skill in
the art will understand that the snapshot component 205 may include
various software-based and/or hardware-based sub-components and
interact with other components in various ways in order to create
snapshots of the data 215.
[0060] The snapshot component 205 may create snapshots using
various techniques, such as copy-on-write, redirect-on-write, split
mirror, copy-on-write with background copy, log structure file
architecture techniques, continuous data protection techniques,
and/or other techniques. The snapshot component 205 may store the
created snapshots on a particular volume of the client 130.
[0061] The secondary storage computing device 165 includes a copy
component 240 that copies snapshots from the client 130 to another
storage device, such as storage device 115. The secondary storage
computing device 165 also stores certain snapshot information
and/or snapshot metadata in various data structures as described
herein. The secondary storage computing device 165 may store
snapshot information and/or snapshot metadata in secondary storage
computing device index 161.
[0062] The secondary storage computing device 165 also includes an
interface component 242. The interface component 242 provides
access to the copied snapshot data. The interface component 242 can
be used to access data objects created in other types of secondary
copies, such as backup copies, archive copies, and other types of
copies. The interface component 242 can also be used to display to
a user available snapshots or point in time copies of the data 215
that can be used for recovery or other purposes. The secondary
storage computing device 165 also includes a snapshot component
244. The snapshot component 244 may function similarly to the
snapshot component 205.
[0063] The secondary storage computing device 165 also includes
applications 245 that perform various functions using copied
snapshot data. The applications 245 include an indexing component
250, a search component 255, an e-discovery component 260, and an
information management component 265. As described in more detail
herein, the applications 245 access copied snapshot data stored on
storage device 115 and data structures stored in secondary storage
computing device index 161 in order to perform various
functions.
Analyzing Snapshots
[0064] FIG. 3 is a flow diagram of a process 300 for analyzing a
snapshot (alternatively referred to as mining a snapshot), and
FIGS. 4A-4E illustrate aspects of the process 300 in more detail.
The process 300 is described using the example of a transactional
application 210 having associated data 215, which includes a
database 220 and logs 225. As can be seen in FIGS. 4A-4E, the
database 220 and associated logs 225 are stored as blocks B.sub.1
through B.sub.6 405 on a storage device associated with the client
130.
[0065] The process 300 begins at step 305 (time to), where the
snapshot component 205 accesses the database 220 and associated
logs 225 and creates a first snapshot 408a of the database 220 and
associated logs 225. See FIG. 4A. For example, the snapshot
component 205 may use a copy-on-write technique to create the first
snapshot, and the process 300 is described using this example
(although other techniques for creating snapshots may be used). The
first snapshot 408a includes a set of pointers P.sub.1 through
P.sub.6 410 (that point to blocks B.sub.1 through B.sub.6, 405,
respectively) and storage location 415 for blocks.
[0066] At step 310 (time t.sub.1), the application 210 modifies the
database 220 and logs 225. For example, the application 210 may
commit changes in certain logs 225 to the database 220 and/or
create new logs 225. These changes may result to modifications to
blocks B.sub.1 and B.sub.4 (which become blocks B.sub.1' and
B.sub.4', respectively). Prior to their modification, the snapshot
component 205 copies blocks B.sub.1 and B.sub.4 to storage location
415. Pointers Pi and P.sub.4 may now point to blocks B.sub.1 and
B.sub.4 in storage location 415, rather than B.sub.1 and B.sub.4 in
storage location 405.
[0067] At step 315 (time t2), the copy component 240 copies the
first snapshot 408a to another location, such as the storage device
115, thereby creating a copy 428a of the first snapshot 408a. See
FIG. 4B. For example, the copy component 240 may copy the first
snapshot 408a as part of a backup process. The copy component 240
creates a copy set of blocks (blocks CBI through CB.sub.6, 425) and
a copy set of pointers that point to the copy set of blocks (CPI
through CP.sub.6 420). Additionally or alternatively, the first
snapshot 408a may be transferred to the other location as part of a
background copy process or using other techniques as known to those
of skill in the art.
[0068] At step 320, the snapshot component 205 determines whether
to take additional snapshots of the database 220 and logs 225. For
example, the snapshot component 205 may be programmed to create
snapshots periodically, such as once a day at, for example, 2:00
a.m. As another example, an administrator may request that the
snapshot component 205 create additional snapshots of the database
220 and logs 225, such as on an ad-hoc basis. If the snapshot
component 205 is to take additional snapshots, the process 300
returns to step 305, and additional snapshots are created (e.g.,
snapshot 408b), the database 220 and logs 225 may be modified, and
the additional snapshots (e.g., snapshot 408b) are copied to the
other location (e.g., creating snapshot copy 428b). As shown in
FIGS. 4B-4C, these additional steps occur at times t.sub.3 through
t.sub.5, where blocks B.sub.2 and B.sub.5 are now changed and
copied out (before being changed) to storage location 425.
[0069] If the snapshot component 205 is not to take additional
snapshots at this time, the process 300 continues at step 325,
where the secondary storage computing device 165 receives an
indication to analyze a copy of a snapshot copied to the other
location (e.g., snapshot copy 428a or snapshot copy 428b). For
example, the secondary storage computing device 165 may receive a
request to obtain a data object (for example, an email message, a
mailbox, a message store, etc.) stored in the database 220 and logs
225.
[0070] At step 330 (time t.sub.6), the snapshot component 244
mounts the snapshot copy 428a at the other location. Mounting the
snapshot copy 428a creates a read-write copy of the database 440
and logs 445. See FIG. 4C.
[0071] At step 335 (time t.sub.7), the snapshot component 244
creates a snapshot 458 of the database 440 and logs 445. This
creates a set of pointers (SSP.sub.1 through SSP.sub.6 465) and a
storage location 470. See FIG. 4D.
[0072] At step 340 (time t.sub.8), the snapshot component 244 plays
the logs 445 into the database 440. For example, if the snapshot
458 is created by a hardware-based sub-component, the snapshot 458
may be read/write, and the snapshot component 244 can modify the
snapshot 458 any time after creating the snapshot 458. As another
example, if the snapshot 458 is created by a software-based
sub-component, the snapshot component 244 may have a window of time
immediately following the creation during which the snapshot
component 244 can modify the snapshot 458. The snapshot component
244 may play all or portions of one or more logs 445 into the
database 440. Playing the logs 445 into the database 440 modifies
certain blocks (as shown, blocks CB.sub.3 and CB.sub.5, which
become blocks CB.sub.3' and CB.sub.5', respectively). (If the logs
and snapshots include insufficient detail to make certain changes
to the database, the system may also create and maintain an index
of changes that map changes recorded by the snapshots with files or
data objects changed, so that the system can identify specific
blocks that may need to be restored before analysis is performed.)
Before the blocks are modified, the snapshot component 244 copies
the blocks (blocks CB.sub.3 and CB.sub.5) to storage location 470.
See FIG. 4D.
[0073] After the snapshot component 244 plays logs 445 into the
database 440, the database 440 may be in a state in which
additional logs 445 cannot be played into the database 440. For
example, a bit or flag may be set in the database 440 indicating
that further logs 445 cannot be played into the database 445. In
some examples, the snapshot component 244 creates the snapshot 458
of the database 440 and logs 445 after playing the logs 445 into
the database 440.
[0074] At step 345 (time t.sub.9), the applications 245 analyze the
database 445 and logs 445. See FIG. 4E. For example, the
applications 245 may analyze the database 445 and logs 445 in order
to, for example, analyze individual data objects within the
database 445 and logs 445. The applications 245 may analyze the
database 445 and logs 445 to perform various functions on
individual data objects. For example, the applications 245 may
index individual data objects, classify individual data objects,
extract individual data objects from the set of data in order to or
copy restore individual data objects to other locations,
deduplicate individual data objects, and/or perform other
functions. More details as to functions that may be performed on
the database 445 and logs 445 are described in the
previously-referenced U.S. patent application Ser. No. 12/979,101,
now U.S. Pat. No. 8,595,191 (Attorney Docket No. 60692-8074.US01),
entitled "SYSTEMS AND METHODS FOR PERFORMING DATA MANAGEMENT
OPERATIONS USING SNAPSHOTS."
[0075] At step 350 (time tic)), the snapshot component 244 reverts
the mounted database 445 and logs 440 to the state they were at the
time the snapshot 458 was created (time t.sub.7). For example, the
snapshot component 244 may revert the mounted database 445 and logs
440 by performing a VSS revert operation using the snapshot 458.
Additionally or alternatively, the snapshot component 244 may use
revert operations other than VSS revert operations and/or other
techniques to revert the mounted database 445 and logs 440. See
FIG. 4E. The process may then loop back to block 305 and take
additional snapshots, or end.
[0076] Performing a revert operation reverts the mounted database
445 and logs 440 to the state they were in at the time the snapshot
458 was created (time t.sub.7). For example, if the snapshot 458
was created before the mounted database 445 and logs 440 were
modified by playing logs 445 into the database 440, performing a
revert operation on the mounted database 440 and logs 445 will
revert mounted database 445 and logs 440 to the state it was in
before playing the logs 445 into the database 440. This puts the
database 440 into a state such that additional logs 445 can be
played into it. For example, if the snapshot component 244 had
previously created the snapshot 458 of the mounted database 445 and
logs 440 and then played logs one and two into the database 440,
the snapshot component 244 can then play additional logs 445 (for
example, logs three to n) into the database 440.
[0077] As another example, if the snapshot of the mounted database
445 and logs 440 was taken after the mounted database 445 and logs
440 were modified, performing a revert operation will revert the
mounted database 445 and logs 440 to the state they were in after
being modified (for example, after logs 445 were played into the
database 440). This also offers the opportunity to play additional
logs 445 (such as those from later snapshots) into the database 440
in order to put the database 440 into the state it existed in at
multiple points in time.
[0078] Accordingly, using snapshots in this way preserves the
integrity of the database 440 in such a way that it can be used for
both analyzing the data in the database 440 and the logs 445, as
well as using the database 440 and the logs 445 to perform a full
recovery of the database 440 and logs 445, or to perform restores
of individual data objects within the database 440 and logs
445.
[0079] In order to analyze the data in the database 440 and logs
445, certain logs 445 may need to be played into the database 440.
For example, to analyze the state of the data 215 as it existed at
the end of day one, logs one and two would need to be played into
the database 440. However, playing such logs 445 into the database
440 may preclude the possibility of playing additional logs 445
into the database 440. Taking a snapshot of the mounted database
440 and logs 445 solves this problem by enabling the ability to
revert the data 215 to the state it existed in prior to or
immediately after the playing of certain logs 445 into the database
440. The techniques described herein facilitate putting the data
215 into a state at a specific point in time, analyzing the data
215 as it existed at that specific point in time, and then
performing a revert operation upon a snapshot of the data 215 in
order to revert the data to a state in which additional logs 445
may be played into the database 440, or in which all or portions of
the data 215 can be recovered.
[0080] Accordingly, the data 215 can be analyzed (for example,
individual data objects may be indexed, searched, extracted,
recovered, etc.), and then such individual data objects can be also
analyzed at a later point in time in order to pick up any later
changes to the individual data objects. For example, an email
message in an email server application database 220 and logs 225
may have a first state at a first point in time. Using the
techniques described herein, the snapshot component 205 can put the
database 220 into the first state at the first point in time and
extract the email message from the database 220. The snapshot
component 205 can then revert the database 220 to a prior state,
and then play additional logs 225 into the database 220, to recover
the email message as it existed at a second, later point in time.
After step 415, the process 400 concludes.
[0081] In some examples, the techniques described herein may be
used on copies of data created other than by snapshot operations.
For example, the secondary storage computing device 165 may create
copies of the database 220 and logs 225 by performing backup
operations on the database 220 and logs 225. The secondary storage
computing device 165 may create a full backup of the database 220
and logs one and two on day one. On day two, the email server
application 210 creates logs three and four, and an incremental
backup of the database 220 and logs 225 on day two would only
backup logs three and four. On day three, logs five and six are
created, and an incremental backup of the database 220 and logs 225
on day three would backup logs five and six. The following table
illustrates this example:
TABLE-US-00001 Day/Time Type of backup Data Day 1/11:00 p.m. Full
Database, logs one and two Day 2/11:00 p.m. Incremental Logs three
and four Day 3/11:00 p.m. Incremental Logs five and six
Utilizing Consistent Recovery Points to Create Snapshots that can
be Analyzed
[0082] In some examples, the techniques described herein may be
used on copies of data created by replication operations such as
CDR (Continuous Data Replication), DDR (Discrete Data Replication),
and other replication operations. For example, for data protected
by a replication operation, multiple Consistent Recovery Points
(CRPs, alternatively referred to as markers) can be established,
and snapshots can be taken at such CRPs. To create a CRP, the
system suspends writes to the data, and inserts the CRP into the
CDR logs that indicate changes to the data. The system then copies
the first CDR logs to another location. The system can play the CDR
logs to replicate the changes to a copy of the data at another
location (the replication data copy). When the system arrives at or
reaches the CRP, the system can take a snapshot of the replicated
data copy. The system can then modify the snapshot of the
replicated data copy (for example, by playing application logs into
an application database) so that the snapshot of the replicated
data copy can be analyzed.
[0083] FIG. 5 is a flow diagram of a process 500 for analyzing a
snapshot (alternatively referred to as mining a snapshot). The
process 500 is described using the example of a transactional
application 210 having associated data 215, which includes a
database 220 and logs 225. The transactional application 210
executes on a source computing system (e.g., the client 130). A
copy of the data 215 as the data 215 existed at a first point in
time is stored on a destination computing system (e.g., the
secondary storage computing device 165). The copy of the data 215
is referred to as the replication data copy. As changes to the data
215 are made, such changes are tracked in CDR logs on the source
computing system.
[0084] The process 500 begins at step 505, where the snapshot
component 205 quiesces the application 210. Quiescing the
application 210 puts the data 215 into a state in which the data
215 is consistent or stable. The snapshot component 205 can quiesce
the application 210 using the VSS sub-component. The VSS
sub-component can then notify the VSS provider sub-component to
create the snapshot. However, the VSS provider sub-component does
not create a snapshot. Instead, at step 510, which occurs at a
second point in time after the first point in time, the snapshot
component 205 inserts a CRP into the CDR logs. The CRP may be
places at predetermined periodic intervals, such as every hour or
every midnight, or sporadically upon user command. At step 512 the
snapshot component (e.g., the VSS sub-component) unquiesces the
application 210.
[0085] At step 515, the data agent 195 copies the CDR logs from the
source computing system to the destination computing system. The
copying can be done periodically, as the CDR logs are created,
using other techniques. At step 520, the destination computing
system plays the CDR logs to replicate changes to the data 215 to
the replication data copy stored at the destination computing
system. At step 525, the destination computing system arrives at or
reaches the CRP in the CDR logs and takes a snapshot of the
replication data copy with the logs replayed (i.e. changes to the
data populated based on the changes indicated in the logs).
[0086] At step 530, the destination computing system puts the
snapshot of the replication data copy into a state at which the
application data can be analyzed (e.g., a clean shutdown state). To
do so, the destination computing system can play the logs 225 into
the database 220 of the snapshot of the replication data copy, as
described herein. At step 535 the destination computing system
analyzes the database 220, as described herein. The destination
computing system can access one or more individual data objects in
the database 220 (e.g., emails, files, etc.) At step 540, the
destination computing system continues playing CDR logs to
replicate additional or other changes to the replication data copy
at the destination computing system. The process 500 then
concludes.
[0087] Additionally or alternatively, instead of analyzing the
snapshot of the replication data copy, the destination computing
system can analyze the replication data copy. To do so, the
destination computing system plays the logs 225 into the database
220 of the replication data copy. Such modifications prevent the
destination computing system from playing the CDR logs to replicate
changes to the replication data copy. After analyzing the
replication data copy, the destination computing system can then
utilize the revert functionality of the snapshot to revert the
replication data copy to the state it was in prior to the playing
of the logs 225 into the database 220. Such reversion allows the
destination computing system to play the CDR logs into the
replication data copy.
[0088] The process 500 provides several advantages. One advantage
is that control over when the data 215 on the source computing
system is to be snapshotted is located on the source computing
system, while the actual snapshotting occurs on the destination
computing system. Such division between an instruction to take a
snapshot and the creation of the snapshot according to the
instruction can save resources on the source computing system.
Another advantage is that the snapshot taken on the destination
computing system, although not application-aware (because the
application is not executing on the destination computing system),
can be considered as application-aware, because the snapshot is
taken at a time when the replication data copy is consistent. Other
advantages will be apparent to those of skill in the art.
Additional Examples
[0089] In some examples, both snapshot operations and non-snapshot
operations may be used. For example, an initial full copy and
snapshot may be taken of the database 220 and logs 225. Subsequent
to the initial snapshot, incremental copies or snapshots of the
database 220 and logs 225 may be made. Those of skill in the art
will understand that various techniques may be used to protect the
database 220 and logs 225.
Other Uses of Data Copies
[0090] Copies of data created using the techniques described herein
may be utilized in other fashions. For example, a first snapshot of
a database 220 and logs 225 could be mounted for use by a client
130 other than the original client 130 (for example, for use as a
standby server). Prior to being mounted, a second snapshot could be
made of the first snapshot in order to be able to back out or undo
any changes to the first snapshot by the mounting and subsequent
use.
[0091] As another example, after the first snapshot of the database
220 and logs 225 is mounted by the other client 130, tests could be
run on the first snapshot in order to validate or verify the first
snapshot (e.g., to ensure that the database 220 and logs 225 was
correctly copied, such as by reading individual data objects in the
database 220 and logs 225). For example, data could be read out of
the database 220 and logs 225 and compared to data read out of the
copy of the database 220 and logs 225 to ensure that the data is
valid (e.g., by creating checksums of the data and comparing the
checksums). This could obviate the need to validate or verify the
first snapshot by restoring the first snapshot to its original
location, which could be a lengthy process. Tests could also be run
on the first snapshot to check the integrity of the original
database 220 and logs 225.
[0092] Snapshots may be taken of copies of data created by
non-snapshot operations in order to perform these and other
functions described herein.
CONCLUSION
[0093] From the foregoing, it will be appreciated that specific
examples of data storage systems have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the invention.
For example, although snapshot operations may have been described,
the systems may be used to perform many types of storage operations
(e.g., backup operations, restore operations, archival operations,
copy operations, Continuous Data Replication (CDR) operations,
recovery operations, migration operations, HSM operations, etc.).
Accordingly, the invention is not limited except as by the appended
claims.
[0094] Terms and phrases used in this document, and variations
thereof, unless otherwise expressly stated, should be construed as
open ended as opposed to limiting. As examples of the foregoing:
the term "including" should be read as meaning "including, without
limitation" or the like; the term "example" is used to provide
suitable instances of the item in discussion, not an exhaustive or
limiting list thereof; the terms "a" or "an" should be read as
meaning "at least one," "one or more" or the like; and adjectives
such as "conventional," "traditional," "normal," "standard,"
"known" and terms of similar meaning should not be construed as
limiting the item described to a given time period or to an item
available as of a given time, but instead should be read to
encompass conventional, traditional, normal, or standard
technologies that may be available or known now or at any time in
the future. Likewise, where this document refers to technologies
that would be apparent or known to one of ordinary skill in the
art, such technologies encompass those apparent or known to the
skilled artisan now or at any time in the future.
[0095] The presence of broadening words and phrases such as "one or
more," "at least," "but not limited to" or other like phrases in
some instances shall not be read to mean that the narrower case is
intended or required in instances where such broadening phrases may
be absent. The use of the term "module" does not imply that the
components or functionality described or claimed as part of the
module are all configured in a common package. Indeed, any or all
of the various components of a module, whether control logic or
other components, can be combined in a single package or separately
maintained and can further be distributed in multiple groupings or
packages or across multiple locations.
[0096] Unless the context clearly requires otherwise, throughout
the description and the claims, the words "comprise," "comprising,"
and the like are to be construed in an inclusive sense, as opposed
to an exclusive or exhaustive sense; that is to say, in the sense
of "including, but not limited to." The word "coupled," as
generally used herein, refers to two or more elements that may be
either directly connected, or connected by way of one or more
intermediate elements. Additionally, the words "herein," "above,"
"below," and words of similar import, when used in this
application, shall refer to this application as a whole and not to
any particular portions of this application. Where the context
permits, words in the above Detailed Description using the singular
or plural number may also include the plural or singular number
respectively. The word "or" in reference to a list of two or more
items, that word covers all of the following interpretations of the
word: any of the items in the list, all of the items in the list,
and any combination of the items in the list.
[0097] The above detailed description of embodiments of the
invention is not intended to be exhaustive or to limit the
invention to the precise form disclosed above. While specific
embodiments of, and examples for, the invention are described above
for illustrative purposes, various equivalent modifications are
possible within the scope of the invention, as those skilled in the
relevant art will recognize. For example, while processes or blocks
are presented in a given order, alternative embodiments may perform
routines having steps, or employ systems having blocks, in a
different order, and some processes or blocks may be deleted,
moved, added, subdivided, combined, and/or modified. Each of these
processes or blocks may be implemented in a variety of different
ways. Also, while processes or blocks are at times shown as being
performed in series, these processes or blocks may instead be
performed in parallel, or may be performed at different times.
[0098] The teachings of the invention provided herein can be
applied to other systems, not necessarily the system described
above. The elements and acts of the various embodiments described
above can be combined to provide further embodiments.
[0099] Any patents and applications and other references noted
above, including any that may be listed in accompanying filing
papers, are incorporated herein by reference. Aspects of the
invention can be modified, if necessary, to employ the systems,
functions, and concepts of the various references described above
to provide yet further implementations of the invention.
[0100] These and other changes can be made to the invention in
light of the above Detailed Description. While the above
description details certain embodiments of the invention and
describes the best mode contemplated, no matter how detailed the
above appears in text, the invention can be practiced in many ways.
Details of the system may vary considerably in implementation
details, while still being encompassed by the invention disclosed
herein. As noted above, particular terminology used when describing
certain features or aspects of the invention should not be taken to
imply that the terminology is being redefined herein to be
restricted to any specific characteristics, features, or aspects of
the invention with which that terminology is associated. In
general, the terms used in the following claims should not be
construed to limit the invention to the specific embodiments
disclosed in the specification, unless the above Detailed
Description section explicitly defines such terms. Accordingly, the
actual scope of the invention encompasses not only the disclosed
embodiments, but also all equivalent ways of practicing or
implementing the invention under the claims.
[0101] While certain aspects of the invention are presented below
in certain claim forms, the inventors contemplate the various
aspects of the invention in any number of claim forms. For example,
while only one aspect of the invention is recited as embodied in a
computer-readable medium, other aspects may likewise be embodied in
a computer-readable medium. As another example, while only one
aspect of the invention is recited as a means-plus-function claim
under 35 U.S.C. .sctn. 112, sixth paragraph, other aspects may
likewise be embodied as a means-plus-function claim, or in other
forms, such as being embodied in a computer-readable medium. (Any
claims intended to be treated under 35 U.S.C. .sctn. 112, 6 will
begin with the words "means for.") Accordingly, the inventors
reserve the right to add additional claims after filing the
application to pursue such additional claim forms for other aspects
of the invention.
* * * * *