U.S. patent application number 13/270528 was filed with the patent office on 2018-01-18 for compacting dispersed storage space.
This patent application is currently assigned to CLEVERSAFE, INC.. The applicant listed for this patent is Andrew Baptist, Greg Dhuse, Ilya Volvovski. Invention is credited to Andrew Baptist, Greg Dhuse, Ilya Volvovski.
Application Number | 20180018285 13/270528 |
Document ID | / |
Family ID | 45997856 |
Filed Date | 2018-01-18 |
United States Patent
Application |
20180018285 |
Kind Code |
A9 |
Volvovski; Ilya ; et
al. |
January 18, 2018 |
COMPACTING DISPERSED STORAGE SPACE
Abstract
A method begins by a processing module receiving an encoded data
slice for storage in memory that is organized as a plurality of log
files and identifying a log file based on information regarding the
encoded data slice to produce an identified log file, wherein the
identified log file is storing at least one other encoded data
slice. The method continues with the processing module comparing
storage parameters of the identified log file with desired storage
parameters associated with the encoded data slice. The method
continues with the processing module attempting to identify a
second log file based on an alternate log file storage protocol
when the storage parameters of the identified log file compare
unfavorably with the desired storage parameters and when the second
log file is identified, storing the encoded data slice in the
second log file.
Inventors: |
Volvovski; Ilya; (Chicago,
IL) ; Baptist; Andrew; (Chicago, IL) ; Dhuse;
Greg; (Chicago, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Volvovski; Ilya
Baptist; Andrew
Dhuse; Greg |
Chicago
Chicago
Chicago |
IL
IL
IL |
US
US
US |
|
|
Assignee: |
CLEVERSAFE, INC.
Chicago
IL
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20120110038 A1 |
May 3, 2012 |
|
|
Family ID: |
45997856 |
Appl. No.: |
13/270528 |
Filed: |
October 11, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12983232 |
Dec 31, 2010 |
8725940 |
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13270528 |
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61408980 |
Nov 1, 2010 |
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61308938 |
Feb 27, 2010 |
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61314166 |
Mar 16, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 67/1097 20130101;
G06F 3/0652 20130101; G06F 16/113 20190101; G06F 16/2365 20190101;
G06F 2212/7205 20130101; G06F 12/1408 20130101; G06F 16/11
20190101; G06F 16/1734 20190101; H04L 41/06 20130101; G06F 16/50
20190101 |
International
Class: |
G06F 12/14 20060101
G06F012/14; H04L 12/24 20060101 H04L012/24; G06F 3/06 20060101
G06F003/06; H04L 29/08 20060101 H04L029/08; G06F 17/30 20060101
G06F017/30 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] This invention was made with Government support under
Contract No. 2009*0674524*000 awarded by the Central Intelligence
Agency. The Government has certain rights in the invention.
Claims
1. A method comprises: receiving an encoded data slice for storage
in memory that is organized as a plurality of log files;
identifying a log file based on information regarding the encoded
data slice to produce an identified log file, wherein the
identified log file is storing at least one other encoded data
slice; comparing storage parameters of the identified log file with
desired storage parameters associated with the encoded data slice;
and when the storage parameters of the identified log file compare
unfavorably with the desired storage parameters: attempting to
identify a second log file based on an alternate log file storage
protocol; and when the second log file is identified, storing the
encoded data slice in the second log file.
2. The method of claim 1 further comprises: the comparing of the
storage parameters of the identified log file with the desired
storage parameters being unfavorable when the identified log file
includes a number of storage gaps that compares unfavorably to a
gap threshold.
3. The method of claim 1 further comprises: the comparing of the
storage parameters of the identified log file with the desired
storage parameters being unfavorable when a storage balance between
the identified log file and the second log file compares
unfavorably to a storage balance threshold.
4. The method of claim 1 further comprises: the comparing of the
storage parameters of the identified log file with the desired
storage parameters being unfavorable when a storage capacity of the
identified log file compares unfavorably to a storage
threshold.
5. The method of claim 1 further comprises: the comparing of the
storage parameters of the identified log file with the desired
storage parameters being favorable when: the log file is identified
as a most recently compacted log file; the log file is identified
as having a favorable amount of available storage space; the log
file is identified in a slice location table lookup; the log file
is predetermined; or the log file is identified based on a slice
name associated with the encoded data slice.
6. The method of claim 1, wherein the information of encoded data
slice comprises at least one of: a data identifier (ID) of a file
associated with the encoded data slice; a user ID associated with
the encoded data slice; and an indication of the log file contained
in a message accompanying the encoded data slice.
7. The method of claim 1 further comprises: when the second log
file is not identified: creating another log file; and storing the
encoded data slice in the other log file.
8. The method of claim 1 further comprises: when the storage
parameters of the identified log file compare favorably with the
desired storage parameters: identifying a log file offset for an
available storage location of the identified log file; storing the
encoded data slice in the identified log file based on log file
offset; and updating a slice location table to include storage of
the encoded data slice in the identified log file.
9. A computer comprises: an interface; a memory; and a processing
module operable to: receive, via the interface, an encoded data
slice for storage in the memory that is organized as a plurality of
log files; identify a log file based on information regarding the
encoded data slice to produce an identified log file, wherein the
identified log file is storing at least one other encoded data
slice; compare storage parameters of the identified log file with
desired storage parameters associated with the encoded data slice;
and when the storage parameters of the identified log file compare
unfavorably with the desired storage parameters: attempt to
identify a second log file based on an alternate log file storage
protocol; and when the second log file is identified, store the
encoded data slice in the second log file.
10. The computer of claim 9, wherein the processing module further
functions to: compare the storage parameters of the identified log
file with the desired storage parameters as unfavorable when the
identified log file includes a number of storage gaps that compares
unfavorably to a gap threshold.
11. The computer of claim 9, wherein the processing module further
functions to: compare the storage parameters of the identified log
file with the desired storage parameters as unfavorable when a
storage balance between the identified log file and the second log
file compares unfavorably to a storage balance threshold.
12. The computer of claim 9, wherein the processing module further
functions to: compare the storage parameters of the identified log
file with the desired storage parameters as unfavorable when a
storage capacity of the identified log file compares unfavorably to
a storage threshold.
13. The computer of claim 9, wherein the processing module further
functions to: compare the storage parameters of the identified log
file with the desired storage parameters as favorable when: the log
file is identified as a most recently compacted log file; the log
file is identified as having a favorable amount of available
storage space; the log file is identified in a slice location table
lookup; the log file is predetermined; or the log file is
identified based on a slice name associated with the encoded data
slice.
14. The computer of claim 9, wherein the information of encoded
data slice comprises at least one of: a data identifier (ID) of a
file associated with the encoded data slice; a user ID associated
with the encoded data slice; and an indication of the log file
contained in a message accompanying the encoded data slice.
15. The computer of claim 9, wherein the processing module further
functions to: when the second log file is not identified: create
another log file; and store the encoded data slice in the other log
file.
16. The computer of claim 9, wherein the processing module further
functions to: when the storage parameters of the identified log
file compare favorably with the desired storage parameters:
identify a log file offset for an available storage location of the
identified log file; store the encoded data slice in the identified
log file based on log file offset; and update a slice location
table to include storage of the encoded data slice in the
identified log file.
Description
CROSS REFERENCE TO RELATED PATENTS
[0001] This patent application is claiming priority under 35 U.S.C.
.sctn.119(e) to a provisionally filed patent application entitled,
"DISPERSED STORAGE NETWORK COMMUNICATION," having a provisional
filing date of Nov. 1, 2010, and a provisional Ser. No. 61/408,980,
pending, which is incorporated herein by reference in its entirety
and made part of the present U.S. Utility patent application for
all purposes.
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT
DISC
[0003] NOT APPLICABLE
BACKGROUND OF THE INVENTION
[0004] 1. Technical Field of the Invention
[0005] This invention relates generally to computing systems and
more particularly to data storage solutions within such computing
systems.
[0006] 2. Description of Related Art
[0007] Computers are known to communicate, process, and store data.
Such computers range from wireless smart phones to data centers
that support millions of web searches, stock trades, or on-line
purchases every day. In general, a computing system generates data
and/or manipulates data from one form into another. For instance,
an image sensor of the computing system generates raw picture data
and, using an image compression program (e.g., JPEG, MPEG, etc.),
the computing system manipulates the raw picture data into a
standardized compressed image.
[0008] With continued advances in processing speed and
communication speed, computers are capable of processing real time
multimedia data for applications ranging from simple voice
communications to streaming high definition video. As such,
general-purpose information appliances are replacing purpose-built
communications devices (e.g., a telephone). For example, smart
phones can support telephony communications but they are also
capable of text messaging and accessing the internet to perform
functions including email, web browsing, remote applications
access, and media communications (e.g., telephony voice, image
transfer, music files, video files, real time video streaming.
etc.).
[0009] Each type of computer is constructed and operates in
accordance with one or more communication, processing, and storage
standards. As a result of standardization and with advances in
technology, more and more information content is being converted
into digital formats. For example, more digital cameras are now
being sold than film cameras, thus producing more digital pictures.
As another example, web-based programming is becoming an
alternative to over the air television broadcasts and/or cable
broadcasts. As further examples, papers, books, video
entertainment, home video, etc. are now being stored digitally,
which increases the demand on the storage function of
computers.
[0010] A typical computer storage system includes one or more
memory devices aligned with the needs of the various operational
aspects of the computer's processing and communication functions.
Generally, the immediacy of access dictates what type of memory
device is used. For example, random access memory (RAM) memory can
be accessed in any random order with a constant response time, thus
it is typically used for cache memory and main memory. By contrast,
memory device technologies that require physical movement such as
magnetic disks, tapes, and optical discs, have a variable response
time as the physical movement can take longer than the data
transfer, thus they are typically used for secondary memory (e.g.,
hard drive, backup memory, etc.).
[0011] A computer's storage system will be compliant with one or
more computer storage standards that include, but are not limited
to, network file system (NFS), flash file system (FFS), disk file
system (DFS), small computer system interface (SCSI), internet
small computer system interface (iSCSI), file transfer protocol
(FTP), and web-based distributed authoring and versioning (WebDAV).
These standards specify the data storage format (e.g., files, data
objects, data blocks, directories, etc.) and interfacing between
the computer's processing function and its storage system, which is
a primary function of the computer's memory controller.
[0012] Despite the standardization of the computer and its storage
system, memory devices fail; especially commercial grade memory
devices that utilize technologies incorporating physical movement
(e.g., a disc drive). For example, it is fairly common for a disc
drive to routinely suffer from bit level corruption and to
completely fail after three years of use. One solution is to a
higher-grade disc drive, which adds significant cost to a
computer.
[0013] Another solution is to utilize multiple levels of redundant
disc drives to replicate the data into two or more copies. One such
redundant drive approach is called redundant array of independent
discs (RAID). In a RAID device, a RAID controller adds parity data
to the original data before storing it across the array. The parity
data is calculated from the original data such that the failure of
a disc will not result in the loss of the original data. For
example, RAID 5 uses three discs to protect data from the failure
of a single disc. The parity data, and associated redundancy
overhead data, reduces the storage capacity of three independent
discs by one third (e.g., n-1=capacity). RAID 6 can recover from a
loss of two discs and requires a minimum of four discs with a
storage capacity of n-2.
[0014] While RAID addresses the memory device failure issue, it is
not without its own failures issues that affect its effectiveness,
efficiency and security. For instance, as more discs are added to
the array, the probability of a disc failure increases, which
increases the demand for maintenance. For example, when a disc
fails, it needs to be manually replaced before another disc fails
and the data stored in the RAID device is lost. To reduce the risk
of data loss, data on a RAID device is typically copied on to one
or more other RAID devices. While this addresses the loss of data
issue, it raises a security issue since multiple copies of data are
available, which increases the chances of unauthorized access.
Further, as the amount of data being stored grows, the overhead of
RAID devices becomes a non-trivial efficiency issue.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0015] FIG. 1 is a schematic block diagram of an embodiment of a
computing system in accordance with the invention;
[0016] FIG. 2 is a schematic block diagram of an embodiment of a
computing core in accordance with the invention;
[0017] FIG. 3 is a schematic block diagram of an embodiment of a
distributed storage processing unit in accordance with the
invention;
[0018] FIG. 4 is a schematic block diagram of an embodiment of a
grid module in accordance with the invention;
[0019] FIG. 5 is a diagram of an example embodiment of error coded
data slice creation in accordance with the invention;
[0020] FIG. 6 is a flowchart illustrating an example of storing an
encoded data slice in accordance with the invention;
[0021] FIG. 7 is a flowchart illustrating an example of deleting an
encoded data slice in accordance with the invention;
[0022] FIG. 8 is an example table illustrating a slice location
table in accordance with the invention;
[0023] FIG. 9 is a flowchart illustrating an example of compacting
slice storage in accordance with the invention; and
[0024] FIG. 10 is a flowchart illustrating another example of
deleting an encoded data slice in accordance with the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] FIG. 1 is a schematic block diagram of a computing system 10
that includes one or more of a first type of user devices 12, one
or more of a second type of user devices 14, at least one
distributed storage (DS) processing unit 16, at least one DS
managing unit 18, at least one storage integrity processing unit
20, and a distributed storage network (DSN) memory 22 coupled via a
network 24. The network 24 may include one or more wireless and/or
wire lined communication systems; one or more private intranet
systems and/or public internet systems; and/or one or more local
area networks (LAN) and/or wide area networks (WAN).
[0026] The DSN memory 22 includes a plurality of distributed
storage (DS) units 36 for storing data of the system. Each of the
DS units 36 includes a processing module and memory and may be
located at a geographically different site than the other DS units
(e.g., one in Chicago, one in Milwaukee, etc.). The processing
module may be a single processing device or a plurality of
processing devices. Such a processing device may be a
microprocessor, micro-controller, digital signal processor,
microcomputer, central processing unit, field programmable gate
array, programmable logic device, state machine, logic circuitry,
analog circuitry, digital circuitry, and/or any device that
manipulates signals (analog and/or digital) based on hard coding of
the circuitry and/or operational instructions. The processing
module may have an associated memory and/or memory element, which
may be a single memory device, a plurality of memory devices,
and/or embedded circuitry of the processing module. Such a memory
device may be a read-only memory, random access memory, volatile
memory, non-volatile memory, static memory, dynamic memory, flash
memory, cache memory, and/or any device that stores digital
information. Note that if the processing module includes more than
one processing device, the processing devices may be centrally
located (e.g., directly coupled together via a wired and/or
wireless bus structure) or may be distributedly located (e.g.,
cloud computing via indirect coupling via a local area network
and/or a wide area network). Further note that when the processing
module implements one or more of its functions via a state machine,
analog circuitry, digital circuitry, and/or logic circuitry, the
memory and/or memory element storing the corresponding operational
instructions may be embedded within, or external to, the circuitry
comprising the state machine, analog circuitry, digital circuitry,
and/or logic circuitry. Still further note that, the memory element
stores, and the processing module executes, hard coded and/or
operational instructions corresponding to at least some of the
steps and/or functions illustrated in FIGS. 1-10.
[0027] Each of the user devices 12-14, the DS processing unit 16,
the DS managing unit 18, and the storage integrity processing unit
20 may be a portable computing device (e.g., a social networking
device, a gaming device, a cell phone, a smart phone, a personal
digital assistant, a digital music player, a digital video player,
a laptop computer, a handheld computer, a video game controller,
and/or any other portable device that includes a computing core)
and/or a fixed computing device (e.g., a personal computer, a
computer server, a cable set-top box, a satellite receiver, a
television set, a printer, a fax machine, home entertainment
equipment, a video game console, and/or any type of home or office
computing equipment). Such a portable or fixed computing device
includes a computing core 26 and one or more interfaces 30, 32,
and/or 33. An embodiment of the computing core 26 will be described
with reference to FIG. 2.
[0028] With respect to the interfaces, each of the interfaces 30,
32, and 33 includes software and/or hardware to support one or more
communication links via the network 24 and/or directly. For
example, interfaces 30 support a communication link (wired,
wireless, direct, via a LAN, via the network 24, etc.) between the
first type of user device 14 and the DS processing unit 16. As
another example, DSN interface 32 supports a plurality of
communication links via the network 24 between the DSN memory 22
and the DS processing unit 16, the first type of user device 12,
and/or the storage integrity processing unit 20. As yet another
example, interface 33 supports a communication link between the DS
managing unit 18 and any one of the other devices and/or units 12,
14, 16, 20, and/or 22 via the network 24.
[0029] In general and with respect to data storage, the system 10
supports three primary functions: distributed network data storage
management, distributed data storage and retrieval, and data
storage integrity verification. In accordance with these three
primary functions, data can be distributedly stored in a plurality
of physically different locations and subsequently retrieved in a
reliable and secure manner regardless of failures of individual
storage devices, failures of network equipment, the duration of
storage, the amount of data being stored, attempts at hacking the
data, etc.
[0030] The DS managing unit 18 performs distributed network data
storage management functions, which include establishing
distributed data storage parameters, performing network operations,
performing network administration, and/or performing network
maintenance. The DS managing unit 18 establishes the distributed
data storage parameters (e.g., allocation of virtual DSN memory
space, distributed storage parameters, security parameters, billing
information, user profile information, etc.) for one or more of the
user devices 12-14 (e.g., established for individual devices,
established for a user group of devices, established for public
access by the user devices, etc.). For example, the DS managing
unit 18 coordinates the creation of a vault (e.g., a virtual memory
block) within the DSN memory 22 for a user device (for a group of
devices, or for public access). The DS managing unit 18 also
determines the distributed data storage parameters for the vault.
In particular, the DS managing unit 18 determines a number of
slices (e.g., the number that a data segment of a data file and/or
data block is partitioned into for distributed storage) and a read
threshold value (e.g., the minimum number of slices required to
reconstruct the data segment).
[0031] As another example, the DS managing module 18 creates and
stores, locally or within the DSN memory 22, user profile
information. The user profile information includes one or more of
authentication information, permissions, and/or the security
parameters. The security parameters may include one or more of
encryption/decryption scheme, one or more encryption keys, key
generation scheme, and data encoding/decoding scheme.
[0032] As yet another example, the DS managing unit 18 creates
billing information for a particular user, user group, vault
access, public vault access, etc. For instance, the DS managing
unit 18 tracks the number of times user accesses a private vault
and/or public vaults, which can be used to generate a per-access
bill. In another instance, the DS managing unit 18 tracks the
amount of data stored and/or retrieved by a user device and/or a
user group, which can be used to generate a per-data-amount
bill.
[0033] The DS managing unit 18 also performs network operations,
network administration, and/or network maintenance. As at least
part of performing the network operations and/or administration,
the DS managing unit 18 monitors performance of the devices and/or
units of the system 10 for potential failures, determines the
devices and/or unit's activation status, determines the devices'
and/or units' loading, and any other system level operation that
affects the performance level of the system 10. For example, the DS
managing unit 18 receives and aggregates network management alarms,
alerts, errors, status information, performance information, and
messages from the devices 12-14 and/or the units 16, 20, 22. For
example, the DS managing unit 18 receives a simple network
management protocol (SNMP) message regarding the status of the DS
processing unit 16.
[0034] The DS managing unit 18 performs the network maintenance by
identifying equipment within the system 10 that needs replacing,
upgrading, repairing, and/or expanding. For example, the DS
managing unit 18 determines that the DSN memory 22 needs more DS
units 36 or that one or more of the DS units 36 needs updating.
[0035] The second primary function (i.e., distributed data storage
and retrieval) begins and ends with a user device 12-14. For
instance, if a second type of user device 14 has a data file 38
and/or data block 40 to store in the DSN memory 22, it send the
data file 38 and/or data block 40 to the DS processing unit 16 via
its interface 30. As will be described in greater detail with
reference to FIG. 2, the interface 30 functions to mimic a
conventional operating system (OS) file system interface (e.g.,
network file system (NFS), flash file system (FFS), disk file
system (DFS), file transfer protocol (FTP), web-based distributed
authoring and versioning (WebDAV), etc.) and/or a block memory
interface (e.g., small computer system interface (SCSI), internet
small computer system interface (iSCSI), etc.). In addition, the
interface 30 may attach a user identification code (ID) to the data
file 38 and/or data block 40.
[0036] The DS processing unit 16 receives the data file 38 and/or
data block 40 via its interface 30 and performs a distributed
storage (DS) process 34 thereon (e.g., an error coding dispersal
storage function). The DS processing 34 begins by partitioning the
data file 38 and/or data block 40 into one or more data segments,
which is represented as Y data segments. For example, the DS
processing 34 may partition the data file 38 and/or data block 40
into a fixed byte size segment (e.g., 2.sup.1 to 2.sup.n bytes,
where n=>2) or a variable byte size (e.g., change byte size from
segment to segment, or from groups of segments to groups of
segments, etc.).
[0037] For each of the Y data segments, the DS processing 34 error
encodes (e.g., forward error correction (FEC), information
dispersal algorithm, or error correction coding) and slices (or
slices then error encodes) the data segment into a plurality of
error coded (EC) data slices 42-48, which is represented as X
slices per data segment. The number of slices (X) per segment,
which corresponds to a number of pillars n, is set in accordance
with the distributed data storage parameters and the error coding
scheme. For example, if a Reed-Solomon (or other FEC scheme) is
used in an n/k system, then a data segment is divided into n
slices, where k number of slices is needed to reconstruct the
original data (i.e., k is the threshold). As a few specific
examples, the n/k factor may be 5/3; 6/4; 8/6; 8/5; 16/10.
[0038] For each slice 42-48, the DS processing unit 16 creates a
unique slice name and appends it to the corresponding slice 42-48.
The slice name includes universal DSN memory addressing routing
information (e.g., virtual memory addresses in the DSN memory 22)
and user-specific information (e.g., user ID, file name, data block
identifier, etc.).
[0039] The DS processing unit 16 transmits the plurality of EC
slices 42-48 to a plurality of DS units 36 of the DSN memory 22 via
the DSN interface 32 and the network 24. The DSN interface 32
formats each of the slices for transmission via the network 24. For
example, the DSN interface 32 may utilize an internet protocol
(e.g., TCP/IP, etc.) to packetize the slices 42-48 for transmission
via the network 24.
[0040] The number of DS units 36 receiving the slices 42-48 is
dependent on the distributed data storage parameters established by
the DS managing unit 18. For example, the DS managing unit 18 may
indicate that each slice is to be stored in a different DS unit 36.
As another example, the DS managing unit 18 may indicate that like
slice numbers of different data segments are to be stored in the
same DS unit 36. For example, the first slice of each of the data
segments is to be stored in a first DS unit 36, the second slice of
each of the data segments is to be stored in a second DS unit 36,
etc. In this manner, the data is encoded and distributedly stored
at physically diverse locations to improved data storage integrity
and security. Further examples of encoding the data segments will
be provided with reference to one or more of FIGS. 2-10.
[0041] Each DS unit 36 that receives a slice 42-48 for storage
translates the virtual DSN memory address of the slice into a local
physical address for storage. Accordingly, each DS unit 36
maintains a virtual to physical memory mapping to assist in the
storage and retrieval of data.
[0042] The first type of user device 12 performs a similar function
to store data in the DSN memory 22 with the exception that it
includes the DS processing. As such, the device 12 encodes and
slices the data file and/or data block it has to store. The device
then transmits the slices 11 to the DSN memory via its DSN
interface 32 and the network 24.
[0043] For a second type of user device 14 to retrieve a data file
or data block from memory, it issues a read command via its
interface 30 to the DS processing unit 16. The DS processing unit
16 performs the DS processing 34 to identify the DS units 36
storing the slices of the data file and/or data block based on the
read command. The DS processing unit 16 may also communicate with
the DS managing unit 18 to verify that the user device 14 is
authorized to access the requested data.
[0044] Assuming that the user device is authorized to access the
requested data, the DS processing unit 16 issues slice read
commands to at least a threshold number of the DS units 36 storing
the requested data (e.g., to at least 10 DS units for a 16/10 error
coding scheme). Each of the DS units 36 receiving the slice read
command, verifies the command, accesses its virtual to physical
memory mapping, retrieves the requested slice, or slices, and
transmits it to the DS processing unit 16.
[0045] Once the DS processing unit 16 has received a read threshold
number of slices for a data segment, it performs an error decoding
function and de-slicing to reconstruct the data segment. When Y
number of data segments has been reconstructed, the DS processing
unit 16 provides the data file 38 and/or data block 40 to the user
device 14. Note that the first type of user device 12 performs a
similar process to retrieve a data file and/or data block.
[0046] The storage integrity processing unit 20 performs the third
primary function of data storage integrity verification. In
general, the storage integrity processing unit 20 periodically
retrieves slices 45, and/or slice names, of a data file or data
block of a user device to verify that one or more slices have not
been corrupted or lost (e.g., the DS unit failed). The retrieval
process mimics the read process previously described.
[0047] If the storage integrity processing unit 20 determines that
one or more slices is corrupted or lost, it rebuilds the corrupted
or lost slice(s) in accordance with the error coding scheme. The
storage integrity processing unit 20 stores the rebuild slice, or
slices, in the appropriate DS unit(s) 36 in a manner that mimics
the write process previously described.
[0048] FIG. 2 is a schematic block diagram of an embodiment of a
computing core 26 that includes a processing module 50, a memory
controller 52, main memory 54, a video graphics processing unit 55,
an input/output (IO) controller 56, a peripheral component
interconnect (PCI) interface 58, at least one IO device interface
module 62, a read only memory (ROM) basic input output system
(BIOS) 64, and one or more memory interface modules. The memory
interface module(s) includes one or more of a universal serial bus
(USB) interface module 66, a host bus adapter (HBA) interface
module 68, a network interface module 70, a flash interface module
72, a hard drive interface module 74, and a DSN interface module
76. Note the DSN interface module 76 and/or the network interface
module 70 may function as the interface 30 of the user device 14 of
FIG. 1. Further note that the IO device interface module 62 and/or
the memory interface modules may be collectively or individually
referred to as IO ports.
[0049] The processing module 50 may be a single processing device
or a plurality of processing devices. Such a processing device may
be a microprocessor, micro-controller, digital signal processor,
microcomputer, central processing unit, field programmable gate
array, programmable logic device, state machine, logic circuitry,
analog circuitry, digital circuitry, and/or any device that
manipulates signals (analog and/or digital) based on hard coding of
the circuitry and/or operational instructions. The processing
module 50 may have an associated memory and/or memory element,
which may be a single memory device, a plurality of memory devices,
and/or embedded circuitry of the processing module 50. Such a
memory device may be a read-only memory, random access memory,
volatile memory, non-volatile memory, static memory, dynamic
memory, flash memory, cache memory, and/or any device that stores
digital information. Note that if the processing module 50 includes
more than one processing device, the processing devices may be
centrally located (e.g., directly coupled together via a wired
and/or wireless bus structure) or may be distributedly located
(e.g., cloud computing via indirect coupling via a local area
network and/or a wide area network). Further note that when the
processing module 50 implements one or more of its functions via a
state machine, analog circuitry, digital circuitry, and/or logic
circuitry, the memory and/or memory element storing the
corresponding operational instructions may be embedded within, or
external to, the circuitry comprising the state machine, analog
circuitry, digital circuitry, and/or logic circuitry. Still further
note that, the memory element stores, and the processing module 50
executes, hard coded and/or operational instructions corresponding
to at least some of the steps and/or functions illustrated in FIGS.
1-10.
[0050] FIG. 3 is a schematic block diagram of an embodiment of a
dispersed storage (DS) processing module 34 of user device 12
and/or of the DS processing unit 16. The DS processing module 34
includes a gateway module 78, an access module 80, a grid module
82, and a storage module 84. The DS processing module 34 may also
include an interface 30 and the DSnet interface 32 or the
interfaces 68 and/or 70 may be part of user 12 or of the DS
processing unit 14. The DS processing module 34 may further include
a bypass/feedback path between the storage module 84 to the gateway
module 78. Note that the modules 78-84 of the DS processing module
34 may be in a single unit or distributed across multiple
units.
[0051] In an example of storing data, the gateway module 78
receives an incoming data object that includes a user ID field 86,
an object name field 88, and the data field 40 and may also receive
corresponding information that includes a process identifier (e.g.,
an internal process/application ID), metadata, a file system
directory, a block number, a transaction message, a user device
identity (ID), a data object identifier, a source name, and/or user
information. The gateway module 78 authenticates the user
associated with the data object by verifying the user ID 86 with
the managing unit 18 and/or another authenticating unit.
[0052] When the user is authenticated, the gateway module 78
obtains user information from the management unit 18, the user
device, and/or the other authenticating unit. The user information
includes a vault identifier, operational parameters, and user
attributes (e.g., user data, billing information, etc.). A vault
identifier identifies a vault, which is a virtual memory space that
maps to a set of DS storage units 36. For example, vault 1 (i.e.,
user 1's DSN memory space) includes eight DS storage units (X=8
wide) and vault 2 (i.e., user 2's DSN memory space) includes
sixteen DS storage units (X=16 wide). The operational parameters
may include an error coding algorithm, the width n (number of
pillars X or slices per segment for this vault), a read threshold
T, a write threshold, an encryption algorithm, a slicing parameter,
a compression algorithm, an integrity check method, caching
settings, parallelism settings, and/or other parameters that may be
used to access the DSN memory layer.
[0053] The gateway module 78 uses the user information to assign a
source name 35 to the data. For instance, the gateway module 60
determines the source name 35 of the data object 40 based on the
vault identifier and the data object. For example, the source name
may contain a file identifier (ID), a vault generation number, a
reserved field, and a vault identifier (ID). As another example,
the gateway module 78 may generate the file ID based on a hash
function of the data object 40. Note that the gateway module 78 may
also perform message conversion, protocol conversion, electrical
conversion, optical conversion, access control, user
identification, user information retrieval, traffic monitoring,
statistics generation, configuration, management, and/or source
name determination.
[0054] The access module 80 receives the data object 40 and creates
a series of data segments 1 through Y 90-92 in accordance with a
data storage protocol (e.g., file storage system, a block storage
system, and/or an aggregated block storage system). The number of
segments Y may be chosen or randomly assigned based on a selected
segment size and the size of the data object. For example, if the
number of segments is chosen to be a fixed number, then the size of
the segments varies as a function of the size of the data object.
For instance, if the data object is an image file of 4,194,304
eight bit bytes (e.g., 33,554,432 bits) and the number of segments
Y=131,072, then each segment is 256 bits or 32 bytes. As another
example, if segment sized is fixed, then the number of segments Y
varies based on the size of data object. For instance, if the data
object is an image file of 4,194,304 bytes and the fixed size of
each segment is 4,096 bytes, the then number of segments Y=1,024.
Note that each segment is associated with the same source name.
[0055] The grid module 82 receives the data segments and may
manipulate (e.g., compression, encryption, cyclic redundancy check
(CRC), etc.) each of the data segments before performing an error
coding function of the error coding dispersal storage function to
produce a pre-manipulated data segment. After manipulating a data
segment, if applicable, the grid module 82 error encodes (e.g.,
Reed-Solomon, Convolution encoding, Trellis encoding, etc.) the
data segment or manipulated data segment into X error coded data
slices 42-44.
[0056] The value X, or the number of pillars (e.g., X=16), is
chosen as a parameter of the error coding dispersal storage
function. Other parameters of the error coding dispersal function
include a read threshold T, a write threshold W, etc. The read
threshold (e.g., T=10, when X=16) corresponds to the minimum number
of error-free error coded data slices required to reconstruct the
data segment. In other words, the DS processing module 34 can
compensate for X-T (e.g., 16-10=6) missing error coded data slices
per data segment. The write threshold W corresponds to a minimum
number of DS storage units that acknowledge proper storage of their
respective data slices before the DS processing module indicates
proper storage of the encoded data segment. Note that the write
threshold is greater than or equal to the read threshold for a
given number of pillars (X).
[0057] For each data slice of a data segment, the grid module 82
generates a unique slice name 37 and attaches it thereto. The slice
name 37 includes a universal routing information field and a vault
specific field and may be 48 bytes (e.g., 24 bytes for each of the
universal routing information field and the vault specific field).
As illustrated, the universal routing information field includes a
slice index, a vault ID, a vault generation, and a reserved field.
The slice index is based on the pillar number and the vault ID and,
as such, is unique for each pillar (e.g., slices of the same pillar
for the same vault for any segment will share the same slice
index). The vault specific field includes a data name, which
includes a file ID and a segment number (e.g., a sequential
numbering of data segments 1-Y of a simple data object or a data
block number).
[0058] Prior to outputting the error coded data slices of a data
segment, the grid module may perform post-slice manipulation on the
slices. If enabled, the manipulation includes slice level
compression, encryption, CRC, addressing, tagging, and/or other
manipulation to improve the effectiveness of the computing
system.
[0059] When the error coded data slices of a data segment are ready
to be outputted, the grid module 82 determines which of the DS
storage units 36 will store the EC data slices based on a dispersed
storage memory mapping associated with the user's vault and/or DS
storage unit attributes. The DS storage unit attributes may include
availability, self-selection, performance history, link speed, link
latency, ownership, available DSN memory, domain, cost, a
prioritization scheme, a centralized selection message from another
source, a lookup table, data ownership, and/or any other factor to
optimize the operation of the computing system. Note that the
number of DS storage units 36 is equal to or greater than the
number of pillars (e.g., X) so that no more than one error coded
data slice of the same data segment is stored on the same DS
storage unit 36. Further note that EC data slices of the same
pillar number but of different segments (e.g., EC data slice 1 of
data segment 1 and EC data slice 1 of data segment 2) may be stored
on the same or different DS storage units 36.
[0060] The storage module 84 performs an integrity check on the
outbound encoded data slices and, when successful, identifies a
plurality of DS storage units based on information provided by the
grid module 82. The storage module 84 then outputs the encoded data
slices 1 through X of each segment 1 through Y to the DS storage
units 36. Each of the DS storage units 36 stores its EC data
slice(s) and maintains a local virtual DSN address to physical
location table to convert the virtual DSN address of the EC data
slice(s) into physical storage addresses.
[0061] In an example of a read operation, the user device 12 and/or
14 sends a read request to the DS processing unit 14, which
authenticates the request. When the request is authentic, the DS
processing unit 14 sends a read message to each of the DS storage
units 36 storing slices of the data object being read. The slices
are received via the DSnet interface 32 and processed by the
storage module 84, which performs a parity check and provides the
slices to the grid module 82 when the parity check was successful.
The grid module 82 decodes the slices in accordance with the error
coding dispersal storage function to reconstruct the data segment.
The access module 80 reconstructs the data object from the data
segments and the gateway module 78 formats the data object for
transmission to the user device.
[0062] FIG. 4 is a schematic block diagram of an embodiment of a
grid module 82 that includes a control unit 73, a pre-slice
manipulator 75, an encoder 77, a slicer 79, a post-slice
manipulator 81, a pre-slice de-manipulator 83, a decoder 85, a
de-slicer 87, and/or a post-slice de-manipulator 89. Note that the
control unit 73 may be partially or completely external to the grid
module 82. For example, the control unit 73 may be part of the
computing core at a remote location, part of a user device, part of
the DS managing unit 18, or distributed amongst one or more DS
storage units.
[0063] In an example of write operation, the pre-slice manipulator
75 receives a data segment 90-92 and a write instruction from an
authorized user device. The pre-slice manipulator 75 determines if
pre-manipulation of the data segment 90-92 is required and, if so,
what type. The pre-slice manipulator 75 may make the determination
independently or based on instructions from the control unit 73,
where the determination is based on a computing system-wide
predetermination, a table lookup, vault parameters associated with
the user identification, the type of data, security requirements,
available DSN memory, performance requirements, and/or other
metadata.
[0064] Once a positive determination is made, the pre-slice
manipulator 75 manipulates the data segment 90-92 in accordance
with the type of manipulation. For example, the type of
manipulation may be compression (e.g., Lempel-Ziv-Welch, Huffman,
Golomb, fractal, wavelet, etc.), signatures (e.g., Digital
Signature Algorithm (DSA), Elliptic Curve DSA, Secure Hash
Algorithm, etc.), watermarking, tagging, encryption (e.g., Data
Encryption Standard, Advanced Encryption Standard, etc.), adding
metadata (e.g., time/date stamping, user information, file type,
etc.), cyclic redundancy check (e.g., CRC32), and/or other data
manipulations to produce the pre-manipulated data segment.
[0065] The encoder 77 encodes the pre-manipulated data segment 92
using a forward error correction (FEC) encoder (and/or other type
of erasure coding and/or error coding) to produce an encoded data
segment 94. The encoder 77 determines which forward error
correction algorithm to use based on a predetermination associated
with the user's vault, a time based algorithm, user direction, DS
managing unit direction, control unit direction, as a function of
the data type, as a function of the data segment 92 metadata,
and/or any other factor to determine algorithm type. The forward
error correction algorithm may be Golay, Multidimensional parity,
Reed-Solomon, Hamming, Bose Ray Chauduri Hocquenghem (BCH),
Cauchy-Reed-Solomon, or any other FEC encoder. Note that the
encoder 77 may use a different encoding algorithm for each data
segment 92, the same encoding algorithm for the data segments 92 of
a data object, or a combination thereof.
[0066] The encoded data segment 94 is of greater size than the data
segment 92 by the overhead rate of the encoding algorithm by a
factor of X/T, where X is the width or number of slices, and T is
the read threshold. In this regard, the corresponding decoding
process can accommodate at most X-T missing EC data slices and
still recreate the data segment 92. For example, if X=16 and T=10,
then the data segment 92 will be recoverable as long as 10 or more
EC data slices per segment are not corrupted.
[0067] The slicer 79 transforms the encoded data segment 94 into EC
data slices in accordance with the slicing parameter from the vault
for this user and/or data segment 92. For example, if the slicing
parameter is X=16, then the slicer 79 slices each encoded data
segment 94 into 16 encoded slices.
[0068] The post-slice manipulator 81 performs, if enabled,
post-manipulation on the encoded slices to produce the EC data
slices. If enabled, the post-slice manipulator 81 determines the
type of post-manipulation, which may be based on a computing
system-wide predetermination, parameters in the vault for this
user, a table lookup, the user identification, the type of data,
security requirements, available DSN memory, performance
requirements, control unit directed, and/or other metadata. Note
that the type of post-slice manipulation may include slice level
compression, signatures, encryption, CRC, addressing, watermarking,
tagging, adding metadata, and/or other manipulation to improve the
effectiveness of the computing system.
[0069] In an example of a read operation, the post-slice
de-manipulator 89 receives at least a read threshold number of EC
data slices and performs the inverse function of the post-slice
manipulator 81 to produce a plurality of encoded slices. The
de-slicer 87 de-slices the encoded slices to produce an encoded
data segment 94. The decoder 85 performs the inverse function of
the encoder 77 to recapture the data segment 90-92. The pre-slice
de-manipulator 83 performs the inverse function of the pre-slice
manipulator 75 to recapture the data segment 90-92.
[0070] FIG. 5 is a diagram of an example of slicing an encoded data
segment 94 by the slicer 79. In this example, the encoded data
segment 94 includes thirty-two bits, but may include more or less
bits. The slicer 79 disperses the bits of the encoded data segment
94 across the EC data slices in a pattern as shown. As such, each
EC data slice does not include consecutive bits of the data segment
94 reducing the impact of consecutive bit failures on data
recovery. For example, if EC data slice 2 (which includes bits 1,
5, 9, 13, 17, 25, and 29) is unavailable (e.g., lost, inaccessible,
or corrupted), the data segment can be reconstructed from the other
EC data slices (e.g., 1, 3 and 4 for a read threshold of 3 and a
width of 4).
[0071] FIG. 6 is a flowchart illustrating an example of storing an
encoded data slice. The method begins with step 110 where a
processing module (e.g., a dispersed storage (DS) unit) receives an
encoded data slice for storage in memory that is organized as a
plurality of log files. The method continues at step 112 where the
processing module identifies a log file based on information
regarding the encoded data slice to produce an identified log file,
wherein the identified log file is storing at least one other
encoded data slice (e.g., the other encoded slice may be associated
with a data file that is not associated with the encoded data
slice). The information of the encoded data slice includes at least
one of a data identifier (ID) of a file associated with the encoded
data slice, a user ID associated with the encoded data slice, and
an indication of the log file contained in a message accompanying
the encoded data slice.
[0072] A log file may represent a portion of a file and may be
utilized to store one or more slices. For example, a log file
includes a range within a file wherein the range is less than the
size of the file. As another example, a log file includes an entire
file. Such identifying of the log file may be based on one or more
of a most recently compacted log file, a log file with the most
available space, and log file with available space greater than the
threshold, a lookup, determination, a date identifier (ID), a user
ID, and a message. For example, the processing module selects log
file 5F8 when the processing module determines that log file 5F8
has more available space than other log files.
[0073] The method continues at step 114 where the processing module
compares storage parameters of the identified log file with desired
storage parameters associated with the encoded data slice. The
processing module may determine the desired storage parameters
based on one or more of the information of the encoded data slice,
a lookup, a message, and a predetermination. The comparing of the
storage parameters of the identified log file with the desired
storage parameters being favorable when the log file is identified
as a most recently compacted log file, the log file is identified
as having a favorable amount of available storage space, the log
file is identified in a slice location table lookup, the log file
is predetermined, or the log file is identified based on a slice
name associated with the encoded data slice.
[0074] The comparing of the storage parameters of the identified
log file with the desired storage parameters being unfavorable when
the identified log file includes a number of storage gaps that
compares unfavorably to a gap threshold (e.g., too many gaps of
free space, from deleted slices, between actively utilized areas).
The comparing of the storage parameters of the identified log file
with the desired storage parameters being further unfavorable when
a storage balance between the identified log file and the second
log file compares unfavorably to a storage balance threshold. For
example, the processing module indicates an unfavorable comparison
when there are twice as many storage gaps associated with the
identified log file as compared to the second log file. The
comparing of the storage parameters of the identified log file with
the desired storage parameters being unfavorable further when a
storage capacity of the identified log file compares unfavorably to
a storage threshold.
[0075] The method branches to step 122 when the processing module
compares the storage parameters of the identified log file with
desired storage parameters as unfavorable, The method continues to
step 116 when the processing module compares the storage parameters
of the identified log file with desired storage parameters as
favorable, The method continues at step 116 where the processing
module identifies a log file offset for an available storage
location of the identified log file when the storage parameters of
the identified log file compare favorably with the desired storage
parameters. The log file offset indicates a number of bytes from
the beginning of the log file to the storage location (e.g., for
storing the encoded data slice within the log file). The
identifying may be based on one or more of a slice location table
lookup, summing a last stored encoded data slice size with a
storage location associated with an encoded data slice that was a
last stored encoded data slice in the log file, a sum of all
encoded data slice sizes previously stored in the log file, an
available space indicator, a beginning of the log file of the log
file identifier (ID), an end of the log file of the log file ID, an
encoded data slice size indicator, and a last utilized log file
offset.
[0076] The method continues at step 118 where the processing module
stores the encoded data slice in the identified log file based on
log file offset. For example, the processing module stores the
encoded data slice at an address within the log file that is a log
file number of bytes from a starting address of the log file. The
method continues at step 120 where the processing module updates a
slice location table to include storage of the encoded data slice
in the identified log file (e.g., storing a slice name of the
encoded data slice, a log file ID, the log file offset).
[0077] The method continues at step 122 where the processing module
attempts to identify a second log file based on an alternate log
file storage protocol when the storage parameters of the identified
log file compare unfavorably with the desired storage parameters.
Such an alternate log file storage protocol attempts to identify
another log file that meets the desired storage parameters. The
method branches to step 126 when the processing module identifies
the second log file. The method continues to step 124 when the
processing module does not identify the second log file. The method
continues at step 124 where the processing module stores the
encoded data slice in the second log file when the second log file
is identified. The method continues at step 126 where the
processing module creates another log file when the second log file
is not identified. The method continues at step 128 where the
processing module stores the encoded data slice in the other log
file.
[0078] FIG. 7 is a flowchart illustrating an example of deleting an
encoded data slice, that includes similar steps to FIG. 6. The
method begins with step 130 where a processing module (e.g., a
dispersed storage (DS) unit) receives a delete encoded data slice
message, wherein the message includes a slice name. For example,
the processing module receives a finalize request message that
includes a slice name and an empty encoded data slice field to
receive the delete encoded data slice message. The method continues
with steps 112 and 116 of FIG. 6 where the processing module
identifies a log file based on the slice name to produce an
identified log file and identifies a log file offset based on the
slice name. The method continues with step 132 where the processing
module updates a slice location table to indicate that storage
space is deleted at the log file offset within the log file (e.g.,
at least an amount of storage space equivalent to a slice size of
the encoded data slice is deleted and available for potential
storing of another encoded data slice).
[0079] FIG. 8 is an example table illustrating a slice location
table 134. The slice location table 134 includes a slice identifier
field 136, a size field 138, and a location field 140. The size
field 138 includes a plurality of size entries corresponding to a
plurality of stored slices, wherein each size entry may be utilized
to indicate a size (e.g., number of bytes) of a corresponding
stored slice or to identify a size of an available portion of a
corresponding log file. The slice identifier field 136 includes a
slice name field 142 and a revision identifier field 144 to
indicate slice names and revisions that correspond to the plurality
of stored slices. The location field 140 includes a log file
identifier field 146 and an offset field 148. The log file
identifier field 146 includes log file identifier entries
representing where encoded data slices are stored corresponding to
slice name entries and the offset field 148 includes offset entries
corresponding to where the encoded data slices are stored within
log files.
[0080] In an example, slice name 1AC revision 1 of size 100 bytes
is stored in log file 5F8 at offset 200. As another example, slice
name 7D1 revision 1 of size 200 is stored in log file 5F8 at offset
1400. The slice location table may be utilized to select log file
identifier 5F8 to store a new slice at offset 1600 that is of size
200 or smaller based on an entry in the slice location table that
indicates that a 200 byte portion of log file 5F8 is available
(e.g., free) at offset 1600.
[0081] FIG. 9 is a flowchart illustrating an example of compacting
slice storage. The method begins with step 150 where a processing
module (e.g., a dispersed storage (DS) processing unit) identifies
a first storage space zone that includes a plurality of deleted
encoded data slices and a plurality of active encoded data slices.
The processing module identifies the first storage space zone in a
memory that is organized as a plurality of log files.
Alternatively, a log file may include one or more storage space
zones. The processing module identifies one or more of the
plurality of log files associated with the first storage space
zone.
[0082] The method continues at step 152 where the processing module
determines to compact the first storage space zone based on a
function of the plurality of deleted encoded data slices and the
plurality of active encoded data slices. Alternatively, the
processing module determines to compact the first storage space
zone based on a function of the plurality of deleted encoded data
slices, the plurality of active encoded data slices, and available
storage in the first storage space zone. The function includes
determining a total storage value corresponding to total storage
space of the first storage space zone, determining a deleted slice
value corresponding to storage space occupied by the plurality of
deleted encoded data slices, determining an active slice value
corresponding to storage space occupied by the plurality of active
encoded data slices, determining an available storage value
corresponding to available storage space of the first storage space
zone, determining a compacting value based on the total storage
value, the deleted slice value, the active slice value, and the
available storage value, and interpreting the compacting value to
when to compact the first storage space zone.
[0083] In an example of operation, the processing module determines
to compact the first storage space zone when a number of the
deleted encoded data slices is greater than a number of the
plurality of active encoded data slices when the function is
determining the deleted slice value corresponding to storage space
occupied by the plurality of deleted encoded data slices and
determining the active slice value corresponding to storage space
occupied by the plurality of active encoded data slices. As another
example, a probability that a compaction operation will be selected
instead of a write operation is calculated in accordance with a
function of: p=(D/(D+W)) (f*E/T), wherein f is a factor that can be
used to increase the steepness of the curve, T=total physical
storage available, W=is written active encoded data slices,
D=deleted encoded data slices, and E=empty available space
available for new data to be written. Utilizing such a function may
result in compaction probability going to 100% as empty space
approaches zero and it does so more quickly when a higher
proportion of deleted encoded data slices exists.
[0084] The method continues at step 154 where the processing module
retrieves the plurality of active encoded data slices from the
first storage space zone when the first storage space zone is to be
compacted. The method continues at step 156 where the processing
module identifies a second storage space zone. The processing
module identifies one or more other log files of the plurality of
log files associated with the second storage space zone. The
identifying the second storage space zone includes determining data
size of the plurality of active encoded data slices, determining
whether the second storage space zone includes available and
contiguous storage space that is equal to or exceeds the data size
of the plurality of active encoded data slices, and when the second
storage space zone includes available and contiguous storage space
that is equal to or exceeds the data size of the plurality of
active encoded data slices, selecting the second storage space
zone.
[0085] The method continues at step 158 where the processing module
stores the plurality of active encoded data slices in the second
storage space zone. Alternatively, the processing module stores the
plurality of deleted encoded data slices in the second storage
space zone when the first storage space zone is to be compacted
(e.g., when the second storage space zone is much larger than the
data being transferred). The method continues at step 160 where the
processing module erases the plurality of deleted encoded data
slices and the plurality of active encoded data slices from the
first storage space zone. The erasing the first storage space zone
includes updating a slice location table to remove association of
the plurality of deleted encoded data slices and the plurality of
active encoded data slices within the first storage space zone
(e.g., deleting from first zone, thus compacting) and updating the
slice location table to indicate that the plurality of active
encoded data slices is stored in the second storage space zone.
[0086] FIG. 10 is a flowchart illustrating another example of
deleting an encoded data slice. The method begins with step 162
where a processing module (e.g., a dispersed storage (DS)
processing unit) receives a message to delete one of the plurality
of active encoded data slices (e.g., receive a finalize request
message that includes a slice name and an empty encoded data slice
field). The method continues at step 164 where the processing
module identifies storage space of the first storage space zone
storing the one of the plurality of active encoded data slices. The
method continues at step 166 where the processing module updates a
slice location table to indicate that the one of the plurality of
active encoded data slices is deleted from the storage space to
produce an updated plurality of deleted encoded data slices and an
updated plurality of active encoded data slices.
[0087] As may be used herein, the terms "substantially" and
"approximately" provides an industry-accepted tolerance for its
corresponding term and/or relativity between items. Such an
industry-accepted tolerance ranges from less than one percent to
fifty percent and corresponds to, but is not limited to, component
values, integrated circuit process variations, temperature
variations, rise and fall times, and/or thermal noise. Such
relativity between items ranges from a difference of a few percent
to magnitude differences. As may also be used herein, the term(s)
"operably coupled to", "coupled to", and/or "coupling" includes
direct coupling between items and/or indirect coupling between
items via an intervening item (e.g., an item includes, but is not
limited to, a component, an element, a circuit, and/or a module)
where, for indirect coupling, the intervening item does not modify
the information of a signal but may adjust its current level,
voltage level, and/or power level. As may further be used herein,
inferred coupling (i.e., where one element is coupled to another
element by inference) includes direct and indirect coupling between
two items in the same manner as "coupled to". As may even further
be used herein, the term "operable to" or "operably coupled to"
indicates that an item includes one or more of power connections,
input(s), output(s), etc., to perform, when activated, one or more
its corresponding functions and may further include inferred
coupling to one or more other items. As may still further be used
herein, the term "associated with", includes direct and/or indirect
coupling of separate items and/or one item being embedded within
another item. As may be used herein, the term "compares favorably",
indicates that a comparison between two or more items, signals,
etc., provides a desired relationship. For example, when the
desired relationship is that signal 1 has a greater magnitude than
signal 2, a favorable comparison may be achieved when the magnitude
of signal 1 is greater than that of signal 2 or when the magnitude
of signal 2 is less than that of signal 1.
[0088] As may also be used herein, the terms "processing module",
"module", "processing circuit", and/or "processing unit" may be a
single processing device or a plurality of processing devices. Such
a processing device may be a microprocessor, micro-controller,
digital signal processor, microcomputer, central processing unit,
field programmable gate array, programmable logic device, state
machine, logic circuitry, analog circuitry, digital circuitry,
and/or any device that manipulates signals (analog and/or digital)
based on hard coding of the circuitry and/or operational
instructions. The processing module, module, processing circuit,
and/or processing unit may have an associated memory and/or an
integrated memory element, which may be a single memory device, a
plurality of memory devices, and/or embedded circuitry of the
processing module, module, processing circuit, and/or processing
unit. Such a memory device may be a read-only memory, random access
memory, volatile memory, non-volatile memory, static memory,
dynamic memory, flash memory, cache memory, and/or any device that
stores digital information. Note that if the processing module,
module, processing circuit, and/or processing unit includes more
than one processing device, the processing devices may be centrally
located (e.g., directly coupled together via a wired and/or
wireless bus structure) or may be distributedly located (e.g.,
cloud computing via indirect coupling via a local area network
and/or a wide area network). Further note that if the processing
module, module, processing circuit, and/or processing unit
implements one or more of its functions via a state machine, analog
circuitry, digital circuitry, and/or logic circuitry, the memory
and/or memory element storing the corresponding operational
instructions may be embedded within, or external to, the circuitry
comprising the state machine, analog circuitry, digital circuitry,
and/or logic circuitry. Still further note that, the memory element
may store, and the processing module, module, processing circuit,
and/or processing unit executes, hard coded and/or operational
instructions corresponding to at least some of the steps and/or
functions illustrated in one or more of the Figures. Such a memory
device or memory element can be included in an article of
manufacture.
[0089] The present invention has been described above with the aid
of method steps illustrating the performance of specified functions
and relationships thereof. The boundaries and sequence of these
functional building blocks and method steps have been arbitrarily
defined herein for convenience of description. Alternate boundaries
and sequences can be defined so long as the specified functions and
relationships are appropriately performed. Any such alternate
boundaries or sequences are thus within the scope and spirit of the
claimed invention. Further, the boundaries of these functional
building blocks have been arbitrarily defined for convenience of
description. Alternate boundaries could be defined as long as the
certain significant functions are appropriately performed.
Similarly, flow diagram blocks may also have been arbitrarily
defined herein to illustrate certain significant functionality. To
the extent used, the flow diagram block boundaries and sequence
could have been defined otherwise and still perform the certain
significant functionality. Such alternate definitions of both
functional building blocks and flow diagram blocks and sequences
are thus within the scope and spirit of the claimed invention. One
of average skill in the art will also recognize that the functional
building blocks, and other illustrative blocks, modules and
components herein, can be implemented as illustrated or by discrete
components, application specific integrated circuits, processors
executing appropriate software and the like or any combination
thereof.
[0090] The present invention may have also been described, at least
in part, in terms of one or more embodiments. An embodiment of the
present invention is used herein to illustrate the present
invention, an aspect thereof, a feature thereof, a concept thereof,
and/or an example thereof. A physical embodiment of an apparatus,
an article of manufacture, a machine, and/or of a process that
embodies the present invention may include one or more of the
aspects, features, concepts, examples, etc. described with
reference to one or more of the embodiments discussed herein.
Further, from figure to figure, the embodiments may incorporate the
same or similarly named functions, steps, modules, etc. that may
use the same or different reference numbers and, as such, the
functions, steps, modules, etc. may be the same or similar
functions, steps, modules, etc. or different ones.
[0091] While the transistors in the above described figure(s)
is/are shown as field effect transistors (FETs), as one of ordinary
skill in the art will appreciate, the transistors may be
implemented using any type of transistor structure including, but
not limited to, bipolar, metal oxide semiconductor field effect
transistors (MOSFET), N-well transistors, P-well transistors,
enhancement mode, depletion mode, and zero voltage threshold (VT)
transistors.
[0092] Unless specifically stated to the contra, signals to, from,
and/or between elements in a figure of any of the figures presented
herein may be analog or digital, continuous time or discrete time,
and single-ended or differential. For instance, if a signal path is
shown as a single-ended path, it also represents a differential
signal path. Similarly, if a signal path is shown as a differential
path, it also represents a single-ended signal path. While one or
more particular architectures are described herein, other
architectures can likewise be implemented that use one or more data
buses not expressly shown, direct connectivity between elements,
and/or indirect coupling between other elements as recognized by
one of average skill in the art.
[0093] The term "module" is used in the description of the various
embodiments of the present invention. A module includes a
functional block that is implemented via hardware to perform one or
module functions such as the processing of one or more input
signals to produce one or more output signals. The hardware that
implements the module may itself operate in conjunction software,
and/or firmware. As used herein, a module may contain one or more
sub-modules that themselves are modules.
[0094] While particular combinations of various functions and
features of the present invention have been expressly described
herein, other combinations of these features and functions are
likewise possible. The present invention is not limited by the
particular examples disclosed herein and expressly incorporates
these other combinations.
* * * * *