U.S. patent application number 11/486610 was filed with the patent office on 2006-11-16 for backup system and method based on data characteristics.
This patent application is currently assigned to Hitachi, Ltd.. Invention is credited to Nobuyuki Saika.
Application Number | 20060259724 11/486610 |
Document ID | / |
Family ID | 34269936 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060259724 |
Kind Code |
A1 |
Saika; Nobuyuki |
November 16, 2006 |
Backup system and method based on data characteristics
Abstract
The present invention permits backup processing suited to data
characteristics relating to backup target data by means of a method
that is simple for the user. Data characteristic classification
definition information, in which data characteristic IDs correspond
with one or more data characteristic types respectively, and
mapping information, in which backup destination server information
corresponds with one or more data characteristic IDs respectively,
are prepared. The backup source server 3 sets data characteristic
IDs in each of the backup target files on the basis of metadata of
designated backup target files and of the data characteristic
classification definition information, and then determines backup
destination servers 6A to 6C for each of the backup target files on
the basis of the set data characteristic IDs and mapping
information and transmits the backup target files to the determined
servers 6A to 6C.
Inventors: |
Saika; Nobuyuki;
(Yokosuka-shi, JP) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Hitachi, Ltd.
Tokyo
JP
|
Family ID: |
34269936 |
Appl. No.: |
11/486610 |
Filed: |
July 13, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10794241 |
Mar 5, 2004 |
7100007 |
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11486610 |
Jul 13, 2006 |
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Current U.S.
Class: |
711/162 ;
714/E11.12; 714/E11.123; 714/E11.125 |
Current CPC
Class: |
G06F 11/1456 20130101;
G06F 11/1464 20130101; G06F 11/1451 20130101 |
Class at
Publication: |
711/162 |
International
Class: |
G06F 12/16 20060101
G06F012/16 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 12, 2003 |
JP |
2003-320771 |
Claims
1. A backup system, comprising: a backup source computer device
that stores backup target data; a plurality of backup destination
computer devices each connected to the backup source computer
device via a network; a backup mode selector that selects,
according to data characteristics of the backup target data, any
one backup mode from among a plurality of pre-prepared backup
modes; and a backup executor that stores the backup target data by
transferring the backup target data from the backup source computer
device to a backup destination computer device that is selected on
the basis of the selected backup mode from among the backup
destination computer devices, wherein the backup executer selects
the backup data on the basis of a data characteristic
classification definition information which is information relating
to rules on how backup target data are classified.
2. The backup system according to claim 1, wherein the backup data
is selected on the basis of at least one or more of judgment
elements comprising the presence or absence of encryption, the
number of common users, special features common to common users,
the presence or absence of access restrictions, file extension
type, file name, and the presence or absence of predetermined
keywords.
3. A backup method that performs a backup between a backup source
computer device for storing backup target data and a plurality of
backup destination computer devices each connected to the backup
source computer device via a network, the backup method comprising:
selecting, according to data characteristics of the backup target
data, any one backup mode from among a plurality of pre-prepared
backup modes; selecting the backup data on the basis of a data
characteristic classification definition information which is
information relating to rules on how backup target data are
classified; and storing the backup target data by transferring the
backup target data from the backup source computer device to a
backup destination computer device that is selected on the basis of
the selected backup mode from among the backup destination computer
devices.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/794,241, filed Mar. 5, 2004, which relates
to and claims priority from Japanese Patent Application No.
2003-320771 filed on Sep. 12, 2003, the entire disclosures of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a technology for backing up
data, and, more specifically, to a technology for backing up data
to at least one device among a plurality of backup destination
devices via a communication network, for example.
[0004] 2. Description of the Related Art
[0005] Conventionally known backup systems are systems in which a
plurality of backup destination servers exist in a communication
network such as the Internet, and at least one backup destination
server is selected from this plurality of backup destination
servers, and data is backed up by transferring data to the backup
destination servers. In such a system, according to Japanese Patent
Publication Laid Open No. 2002-215474, for example, a backup
destination server constituting a destination for storing data to
be backed up (hereinafter "backup target data") is selected from
among the plurality of backup destination servers on the basis of
the reliability, performance, or processing speed of the plurality
of backup destination servers, and then backup processing is
performed by transferring backup target data to the selected backup
destination server.
[0006] However, with the above-mentioned conventional backup
systems, the data characteristics relating to the backup target
data are not considered when a backup is made. A variety of types
of backup target data may be considered to exist for the user. For
example, if there is also backup target data that needs to undergo
backup processing distinctly from other data, there is probably
also backup target data that needs to undergo backup processing
with an emphasis on security and backup target data for which
reliability must be secured as in the case of a backup to a
plurality of locations may also be considered to exist.
[0007] In order to perform a backup in which the data
characteristics of such backup target data are considered, settings
with respect to how the backup processing is performed may be
considered one at a time. However, the setting of backup processing
in such small units is a tedious operation and troublesome for the
user.
[0008] Accordingly, it is a feature of the present invention to
make it possible to perform backup processing that is suited to the
data characteristics pertaining to the backup target data by means
of a method that is straightforward for the user.
BRIEF SUMMARY OF THE INVENTION
[0009] The backup system according to one aspect of the present
invention comprises: a backup source computer device that stores
backup target data; a plurality of backup destination computer
devices each connected to the backup source computer device via a
network; a backup mode selector that selects, according to data
characteristics of the backup target data, any one backup mode from
among a plurality of pre-prepared backup modes; and a backup
executor that stores the backup target data by transferring same
from the backup source computer device to a backup destination
computer device that is selected on the basis of the selected
backup mode from among the backup destination computer devices.
[0010] The backup source computer device and the backup destination
computer device may be constituted as a computer system that is
capable of using storage devices such as hard disk or semiconductor
memory device, as in the case of a file server (NAS (Network
Attached Storage)) or similar, for example. The backup source
computer device can comprise a file system that is shared by a
plurality of users, for example. Examples of backup target data may
include data files created by each user, data groups constituting
the content of a database, and system files defining the
constitution and the like of the user system, and so forth. With
this embodiment, backups are performed in file units. Data
characteristics can be defined as information denoting the data
usage characteristics possessed by the backup target data, for
example, and can be classified in accordance with the purpose for
using the backup target data, and the form of usage.
[0011] According to an embodiment of the present invention, backup
modes are prepared in accordance with predefined plural-type data
characteristics. When a backup instruction is issued by the
operations manager or similar, or a preset backup time arrives, the
backup mode selector discriminates data characteristics of the
backup target data and select a backup mode that matches the data
characteristics. A backup destination computer device that is used
as the backup destination of the backup target data is determined
by the selection of the backup mode. The backup executor transfers
the backup target data to the selected backup destination computer
device. The backup target data is accordingly prepared for the
backup destination computer device. Methods for transferring backup
target data can be broadly classified into two types. One method is
a method that transmits backup target data from a backup source
computer device to a backup destination computer device. The other
method is one in which the backup destination computer device
accesses the backup source computer device to download backup
target data.
[0012] According to an embodiment of the present invention, the
backup mode selector determines whether the backup target data
possesses any data characteristic on the basis of pre-prepared
characteristic classification conditions.
[0013] Characteristic classification conditions are discrimination
information serving to discriminate whether the backup target data
pertains to any of the predefined plural-type data characteristics.
Here, data characteristics that are pre-classified by the
characteristic classification conditions can be expressed as
defined data characteristics, data characteristic types, data
characteristic categories, and so forth, for example.
[0014] According to an embodiment of the present invention, the
backup mode selector determines whether the backup target data
possesses any data characteristics by comparing acquired metadata
relating to the backup target data, and characteristic
classification conditions.
[0015] Examples of acquired metadata relating to the backup target
data include, for example, a file name, file size, an update date
and time, a file extension (that is, the file type), access group
management information set in a file, names of the users sharing
the file, the total number of common users, and the category to
which the common users belong (job categories such as the planning
department, accounting department, development department, as well
as ranking categories such as person in charge, section manager,
head of department, and executive, for example), and so forth.
[0016] Data characteristics include any one of data characteristics
that prioritize the securing of data reliability or data
characteristics that prioritize the securing of data security.
[0017] According to an embodiment of the present invention, both
data characteristics that place emphasis on data reliability and
data characteristics that place emphasis on data security are
included.
[0018] Data characteristics that prioritize the securing of data
reliability are a data characteristic segment in which data
consistency is secured and the prevention of data destruction and
loss is required. The data characteristics that prioritize the
securing of data reliability can be determined by considering at
least one or more judgment elements among judgment elements such as
the number of common users, file extension type, file name, and the
presence or absence of write permissions, for example.
[0019] The data characteristics that prioritize the securing of
data security are a data characteristic segment in which data
secrecy is retained and the prevention of unauthorized copying and
so forth is required. Data characteristics that prioritize the
securing of data security can be determined by considering at least
one or more judgment elements among judgment elements such as the
presence or absence of encryption, the number of common users,
special features common to common users, the presence or absence of
access restrictions, file extension type, file name, and the
presence or absence of predetermined keywords, for example.
[0020] According to an embodiment of the present invention, the
backup executor selects a backup destination computer device
constituting a backup destination on the basis of backup
destination mapping information constituted so as to pre-match at
least one or more backup destination computer devices of the backup
destination computer devices with each backup mode.
[0021] According to an embodiment of the present invention, the
backup executor comprises: a backup list generator that generates a
backup list that includes information specifying backup target data
to be acquired by the backup destination computer device; and a
backup list transmitter that transmits the backup list to the
backup destination computer device, and wherein the backup
destination computer device comprises: a data acquisitor that
stores backup target data by acquiring same from the backup source
computer device on the basis of the backup list received from the
backup source computer device.
[0022] Here, examples of information specifying the backup target
data include information on the path to the backup target data, the
file name, and so forth. The backup list is prepared for each of
the backup destination computer devices and each of the backup
target data items to be acquired by each backup destination
computer device is explicit in each backup list. Accordingly, the
backup destination computer device is able to specify backup target
data to be acquired, and acquire backup target data from the backup
source computer device by referencing only the backup list that is
addressed to the backup destination computer device.
[0023] According to an embodiment of the present invention, the
backup list includes information indicating a backup availability
time when backup target data can be acquired from the backup source
computer device, and the backup destination computer device
accesses the backup source computer device according to the backup
availability time to acquire the backup target data.
[0024] By including a backup availability time in the backup list,
the reading of backup target data at a time other than the backup
availability time can be prevented beforehand, and hence stability
can be raised.
[0025] According to an embodiment of the present invention, upon
receiving the backup list from the backup source computer device,
the backup destination computer device generates restore data to be
used for restoring the backup target data, and transmits the
restore data thus generated to the backup source computer
device.
[0026] For example, the restore data can include discrimination
information for specifying data (or a data group) that is backed up
to the backup destination computer device.
[0027] According to an embodiment of the present invention, the
backup list transmitter controls the time for transmitting the
backup list to the backup destination computer device.
[0028] For example, as a result of a shift between the backup
availability time that is granted one backup destination computer
device and a backup availability time that is granted another
backup destination computer device, the time of the backup
processing by each backup destination computer device can be
adjusted and the processing load on the backup source computer
device and the communication network traffic can be controlled.
[0029] A backup method according to another aspect of the present
invention for performing a backup between a backup source computer
device for storing backup target data and a plurality of backup
destination computer devices each connected to the backup source
computer device via a network, comprises the steps of: determining
data characteristics pertaining to backup target data on the basis
of characteristic classification conditions for classifying data
characteristics; determining a backup destination computer device
for each of the backup target data on the basis of the determined
data characteristics and of backup destination mapping information
that is constituted so that at least one or more of the backup
destination computer devices constituting backup destinations
correspond(s) with each of the data characteristics; collecting,
for each of the backup destination computer devices, the backup
target data corresponding with the backup destination computer
devices; generating, for each of the backup destination computer
devices, a backup list that includes information specifying backup
target data to be acquired by the backup destination computer
devices; transmitting the generated backup lists to the backup
destination computer devices; and transferring the backup target
data from the backup source computer device to the backup
destination computer devices on the basis of the basis of the
received backup lists.
[0030] A computer device according to yet another aspect of the
present invention, comprising: a component that stores
characteristic classification conditions for classifying data
characteristics; a component that determines data characteristics
pertaining to backup target data on the basis of the characteristic
classification conditions; a component that stores backup
destination mapping information constituted such that at least one
or more backup destination computer devices constituting a backup
destination correspond(s) with each of the data characteristics; a
component that determines a backup destination computer device for
each of the backup target data on the basis of the determined data
characteristics and the backup destination mapping information; a
component that that collects, for each of the backup destination
computer devices, the backup target data corresponding with the
backup destination computer devices and generating, for each of the
backup destination computer devices, a backup list including
information specifying backup target data to be acquired by the
backup destination computer devices; a component that transmits the
generated backup lists to the backup destination computer devices;
and a component that transfers the backup target data to the backup
destination computer devices when the backup destination computer
devices request the acquisition of backup target data on the basis
of the transmitted backup lists.
[0031] The computer program according to another aspect of the
present invention is a computer program that causes a computer
device for storing backup target data to execute a method for
issuing a backup request, the backup method comprising the steps
of: determining data characteristics pertaining to backup target
data on the basis of characteristic classification conditions for
classifying data characteristics; determining a backup destination
computer device for each of the backup target data on the basis of
the determined data characteristics and of backup destination
mapping information that is constituted so that at least one or
more of the backup destination computer devices constituting backup
destinations correspond(s) with each of the data characteristics;
generating, for each of the backup destination computer devices, a
backup list that includes information specifying backup target data
to be acquired by the backup destination computer devices; and
transmitting the generated backup lists to the backup destination
computer devices.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is an overall constitutional view of the backup
system according to an embodiment of the present invention.
[0033] FIG. 2 is a block diagram showing the functions of the
servers 3 and 6A to 6C that constitute the backup system according
to this embodiment.
[0034] FIG. 3 shows an example of data characteristic
classification definition information.
[0035] FIG. 4 shows an example of classification result data.
[0036] FIG. 5 shows an example of backup destination mapping
information.
[0037] FIG. 6 shows an example of backup lists 200A, 200B, and
200C.
[0038] FIG. 7 is an image diagram of the flow of the processing of
a backup request unit 12.
[0039] FIG. 8 shows the constitution of an archive file created by
a backup request acceptance unit 21.
[0040] FIG. 9 is a flowchart showing the flow of the processing of
a data characteristic classification unit 11 that a backup source
server 3 comprises.
[0041] FIG. 10 is a flowchart showing the flow of the processing of
the backup request unit 12.
[0042] FIG. 11 is a flowchart showing the flow of the processing of
the backup request unit 12.
[0043] FIG. 12 is a flowchart showing the flow of the processing of
a download acceptance unit 13.
[0044] FIG. 13 shows the flow of the processing of the backup
request acceptance unit 21 of the backup destination server.
[0045] FIG. 14 shows the flow of the processing of the backup
request acceptance unit 21 of the backup destination server.
[0046] FIG. 15 shows an example of a restore file.
[0047] FIG. 16 shows the flow of the restore processing of the
backup source server 3.
DETAILED DESCRIPTION OF THE INVENTION
[0048] An embodiment of the present invention will be described
hereinbelow with reference to the drawings.
[0049] FIG. 1 is an overall constitutional view of the backup
system according to an embodiment of the present invention.
[0050] As shown in FIG. 1, the backup system according to this
embodiment has a single backup source data center 1 (or a plurality
thereof), and a plurality (three, for example) of backup
destination data centers (2A, 2B, 2C).
[0051] The backup source data center 1 is a data center
constituting the backup source of backup target files. The center 1
comprises one or a plurality of backup source storage devices 4
that store backup target files, and a backup source storage device
3, which can be communicably connected to the backup source storage
devices 4 via a communication network or the like such as an SAN
(Storage Area Network).
[0052] Meanwhile, the backup destination data centers (2A, 2B, and
2C) are data centers for storing backups of files that are stored
in the backup source data center 1. For example, the center 2A
comprises one or a plurality of backup destination storage devices
5A, which are capable of storing backups of backup target files;
and a backup destination server 6A that can be communicably
connected to the backup destination storage devices 5 via a
communication network or the like such as an SAN. As is shown,
another center 2B (and 2C) also comprises a storage device 5B (and
5C) like the center 2A, and a server 6B (and 6C).
[0053] The servers 3 and 6A to 6C, and the storage devices 4 and 5A
to 5C will be described below.
[0054] The backup source server 3 classifies one or a plurality of
backup target files in the backup source storage device 4 into one
or more file groups (groups including one or more backup target
files) that have common data characteristics on the basis of
respective data characteristics for these backup target files.
Further, the backup source server 3 transmits one or more backup
target files pertaining to each file group to one or more backup
destination servers 6A to 6C on the basis of common data
characteristics in these file groups.
[0055] The backup source storage device 4 is a storage system that
comprises an external or internal hard disk, or one or a plurality
of hard disks in the form of an array, for example, and is able to
store backup target files. In the backup source storage device 4,
various files are of a predetermined format and are managed
according to a hierarchical structure in which, for example, a
second directory lies below a first directory and one or a
plurality of files are stored in the second directory. Therefore,
if, for example, the operator designates the first directory as the
backup target with respect to the backup source server 3, all the
directories and files that lie below the first directory are
designated as the backup target.
[0056] The backup destination servers 6A to 6C receive backup
target files from the backup source server 3 and store these backup
target files in the communicably connected backup destination
storage devices 5A to 5C respectively.
[0057] The backup destination storage devices 5A to 5C are storage
devices in which backup target files are stored via the backup
destination servers 6A to 6C from the backup source server 3, and
are magnetic tape libraries equipped with one or a plurality of
magnetic tapes, or storage systems comprising one or a plurality of
hard disks in the form of an array, for example.
[0058] FIG. 2 is a block diagram showing the functions of the
servers 3 and 6A to 6C that constitute the backup system according
to this embodiment.
[0059] The backup source server 3 comprises an operating system
(OS) 10 such as a Microsoft Windows (Trademark) operating system,
and comprises, as application software above this OS 10, a data
characteristic classification unit 11, a backup request unit 12, a
download acceptance unit 13, and a restore unit 14.
[0060] When a backup target is designated from outside the backup
source server 3 (an operator or a remote external device, for
example), the data characteristic classification unit 11 acquires,
with predetermined timing (immediately following the designation of
the backup target or at fixed intervals, for example), metadata for
the designated backup target file (and/or metadata for one or more
directories containing the file) from the backup source storage
device 4. The data characteristic classification unit 11 then
classifies the designated backup target file on the basis of the
acquired meta data and pre-prepared data characteristic
classification definition information.
[0061] Here, the file (and `directory`) `metadata` represents
characteristics relating to the file (and directory) and includes
at least one type of information among the following subinformation
in (1) to (7) below, for example:
[0062] (1) the number of common users (the number of users allowed
to access the file (and directory) and view same);
[0063] (2) extension (such as `jpg` or `gif`, for example));
[0064] (3) keyword (character or character string contained in the
file name, directory name and/or actual data, for example);
[0065] (4) presence or absence of write permissions (whether or not
writing is permitted);
[0066] (5) encryption attribute (information indicating whether the
file (and directory) is encrypted);
[0067] (6) presence or absence of ACL (Access Control List)
settings (whether there is corresponding information (that is, an
ACL) indicating which users or user groups can gain access and the
manner in which they do so (reading, writing, or execution, for
example); and
[0068] (7) special characteristics of common users (common user
posts or departments, for example) (may be another type of
information (such as message data, for example) relating to access
restrictions instead of the ACL of the `presence or absence of ACL
settings` in (6), for example).
[0069] Further, data characteristic classification definition
information is information relating to rules on how backup target
files are classified, and is created by a predetermined individual
(an operations manager, for example) and then stored in a
predetermined location on a communication network (in the backup
source server 3 or backup source storage device 4, for example).
More specifically, as shown in FIG. 3, for example, data
characteristic classification definition information includes one
or more data characteristic IDs for discriminating one or more data
characteristic types and one or more rule bodies that correspond
with the one or more data characteristic IDs. The rule body is
information representing conditions for assigning the corresponding
data characteristic IDs (in other words, information representing
the data characteristic type corresponding with the data
characteristic ID). Each rule body has a predetermined
constitution, comprising a plurality of subconditions and logic
operators that link the subconditions, for example (AND, OR, XOR,
and so forth, for example). In FIG. 3, for example, in the case of
the rule body for the data characteristic `ID-002`, the file is not
encrypted, and there is no ACL setting and no restrictions relating
to access-enabled user groups (that is, common users are not set),
and the rule body shows that the file extension is `.html`, `.doc`,
or `.xls`. If a file corresponding to the conditions indicated by
this rule body (a file with metadata or actual data satisfying the
conditions of the rule body, for example) exists, the data
characteristic ID `ID-002` is assigned to this file.
[0070] The individual creating the data characteristic
classification definition information (hereinafter called the
`creator`) is not limited to the example shown in FIG. 3, and is
able to create a variety of rule bodies by preparing subconditions
of any kind and connecting any of the prepared plurality of
subconditions in some way.
[0071] For example, when a file classification with an emphasis on
file (or directory) reliability is desired of the data
characteristic classification unit 11, a rule body can be created
on the basis of at least one aspect of the following aspects (A) to
(C), for example.
[0072] (A) Subconditions based on the number of common users are
prepared, and the data characteristic classification unit 11 is
thus made to perform file classification on the basis of the number
of common users. For example, a file (or directory) for which the
number of common users is at or more than a certain value can be
judged as being a file for which reliability is emphasized in that
it is thought that the number of accessing users is large (or the
access frequency is high) and hence the effects of file
deterioration are large. For this reason, the creator may set a
desired value for the "number of common users" as a subcondition in
the rule body, and, by means of processing by the data
characteristic classification unit 11 (described in detail
subsequently), a data characteristic ID indicating that the file
reliability is high is assigned to a certain file (or directory)
the number of common users of which is equal to or more than the
desired value.
[0073] (B) Subconditions based on an extension or keyword
(character string contained in metadata or actual data, for
example) are prepared, and the data characteristic classification
unit 11 is thus made to perform file classification on the basis of
an extension or a character string that is contained in the file
name. For example, when the extension is `.sys`, it can be judged
that this is data for which reliability is emphasized in that, when
a definition file relating to the constitution of a server program,
or the like, has been stored and the file content is then changed
or destroyed, the server no longer operates correctly and so forth,
this being the cause of a fatal error. On the other hand, for
example, because a temporary file (extension `tmp`), or a work
directory (extension `wrk`) that is temporarily created is
temporary data, a backup is not required, and a judgment to remove
this data from backup processing is possible. As a result, the
creator may set `extension` or `keyword` as a subcondition within
the rule body as a condition to be selected during classification,
or may set `extension` or `keyword` as a condition to be excluded
from the backup target during classification, whereby file
classification based on file reliability is performed by the
processing of the data characteristic classification unit 11
(described in detail subsequently).
[0074] (C) Subconditions based on the number of users with write
permission are prepared, and the data characteristic classification
unit 11 is thus made to perform file classification based on the
number of users with write permission. For example, in the case of
files shared by a large number of people and for which writing is
permitted, there is a high possibility of file destruction
occurring, and hence it can be judged that backup processing in a
stable state with the emphasis on reliability is required.
Therefore, the creator may set the number of common users and the
presence or absence of write permissions as subconditions in the
rule body, whereby file classification based on this aspect is
performed by the processing of the data characteristic
classification unit 11 (described in detail subsequently).
[0075] Further, when file classification with an emphasis on file
(or directory) security is desired of the data characteristic
classification unit 11, for example, a rule body can be created on
the basis of at least one aspect of the following aspects (a) to
(f), for example.
[0076] (a) Subconditions based on the presence or absence of
encryption are prepared, and the data characteristic classification
unit 11 is thus made to perform file classification based on the
presence or absence of encryption. For example, a predetermined OS
(one example of which is Microsoft's Windows2000 (trademark))
supports file encryption in the file system, and the presence or
absence of this file encryption can be confirmed from a file
attribute (metadata, for example). However, when encryption
settings are in place, it is possible to judge that the file is
data for which security must be secured. For this reason, the
creator may establish the presence of encryption for the
`encryption presence or absence` as a subcondition in the rule
body, and hence a data characteristic ID indicating that security
is high is assigned to a file determined to be a high security file
by the processing of the data characteristic classification unit 11
(described in detail subsequently).
[0077] (b) Subconditions based on the number of common users are
prepared, and the data characteristic classification unit 11 is
thus made to perform file classification based on the number of
common users. For example, it can be judged that a file having a
`number of common users` equal to or less than a certain value is
highly secret and file disclosure is restricted. For this reason,
the creator may set the value of the `number of common users` as a
subcondition in the rule body and hence a data characteristic ID
indicating that security is high is assigned to a file (or
directory) for which the number of common users is equal to or more
than a desired value by the processing of the data characteristic
classification unit 11 (described in detail subsequently).
[0078] (c) Subconditions that are based on the presence or absence
of ACL settings are prepared, and the data characteristic
classification unit 11 is thus made to perform file classification
based on the presence or absence of ACL settings. For example, a
file with ACL setting can be judged as being data with access
restrictions provided and for which security must be secured. For
this reason, the creator may set the presence of ACL settings for
`presence or absence of ACL settings` as a subcondition in the rule
body, and a data characteristic ID indicating that security is high
is assigned to a file determined to be a high security file by the
processing of the data characteristic classification unit 11
(described in detail subsequently).
[0079] (d) Subconditions based on the common user special
characteristics (posts or departments, for example) are prepared
and the data characteristic classification unit 11 is thus made to
perform file classification based on the characteristics of common
users. For example, it can be judged that a file that tends toward
a characteristic according to which there is a large number of
common users with a high position requires security to be secured.
The creator may therefore set `common user special characteristics`
as a subcondition in the rule body and hence a data characteristic
ID indicating that security is high is assigned to a file
determined to be a high security file by the processing of the data
characteristic classification unit 11 (described in detail
subsequently).
[0080] (e) Subconditions based on a file name (or a directory name)
are prepared and the data characteristic classification unit 11 is
thus made to be perform file classification based on the file name
(or directory name). For example, when a file that is known to
require the securing of security exists, the creator may set the
file name of this file (or the name of the directory with this
file) as a subcondition in the rule body, and hence a data
characteristic ID indicating that security is high is assigned to
the file by the processing of the data characteristic
classification unit 11 (described in detail subsequently).
[0081] (f) Subconditions based on a keyword contained in metadata
or actual data are prepared, and the data characteristic
classification unit 11 is thus made to perform file classification
based on a keyword contained in metadata or actual data. For
example, a file in which a keyword such as "(secret)" or
"confidential" repeats itself in the metadata or actual data can be
judged as one requiring security securing. In this case, the
creator may set "(secret)" or "confidential" (or a number of
keywords in addition to this word) as a "keyword" for the metadata
or actual data as a subcondition in the rule body, and hence a data
characteristic ID indicating that security is high is assigned to a
file determined as a high security file by the processing of the
data characteristic classification unit 11 (described in detail
subsequently).
[0082] The data characteristic classification unit 11 assigns, on
the basis of metadata (and/or actual data) of one or more
designated backup target data files and the above-mentioned data
characteristic classification definition information, one or more
data characteristic IDs corresponding with one or more rule bodies
satisfied by the file to the one or more backup target files (that
is, performs classification of the backup target files). The data
characteristic classification unit 11 then outputs data relating to
the classification result, that is, for example, as illustrated in
FIG. 4, classification result data D21 that is produced by
associating information relating to the files (such as the file
names, path names, and data sizes of the files, for example) with
one or more data characteristic IDs assigned to these files, for
each of the one or more backup target files. Further, as
illustrated in FIG. 4, during file classification, when there is a
file for which no condition of the rule body is satisfied, the data
characteristic classification unit 11 assigns a predetermined code
(`Default`, for example), which indicates that such a condition is
absent, to the file in place of data characteristic IDs or as one
data characteristic ID. Furthermore, although not especially shown
in FIG. 4, when a backup target file satisfying a plurality of
conditions each indicated by a plurality of rule bodies exists, a
plurality of data characteristic IDs are assigned to one backup
target file.
[0083] Let us now refer to FIG. 2 once again. When the backup
request unit 12 receives a backup request from outside (the
operations manager, for example) with predetermined timing, the
backup request unit 12 collates the classification result data D21
(see FIG. 4) output by the data characteristic classification unit
11, along with pre-prepared backup destination mapping information.
Then, on the basis of the classification result data and the backup
destination mapping information, the backup request unit 12
prepares, for each of the backup destination servers 6A to 6C,
information relating to which backup target file is transmitted to
which backup destination server, such as a backup list (described
later), for example, and then transmits each backup list to the
backup destination servers 6A to 6C to which these lists are
addressed.
[0084] Here, as illustrated in FIG. 5, the backup destination
mapping information includes information indicating which data
characteristic ID (and the above-mentioned `Default` indicating the
absence thereof)--assigned file is backed up to which backup
destination server, that is, information (a host (server) name, or
IP address and so forth, for example) relating to one (or a
plurality of) backup destination servers associated with a
plurality of data characteristic IDs. This backup destination
mapping information is created automatically by a computer or
manually by a predetermined individual (an operations manager, for
example), and is pre-stored in a predetermined location on a
communication network (in the backup source server 3 or backup
source storage device 4, for example).
[0085] Furthermore, the backup lists are prepared in the same
quantity as the backup destination servers. For example, the three
backup lists 200A, 200B, and 200C illustrated in FIG. 6 are
prepared for three backup destination servers 6A, 6B, and 6C by the
backup request unit 12. If this is described representatively with
respect to the backup list 200A, the `acceptance date and time` and
information relating to the backup destination server corresponding
with this list 200A (the `host name` and `file list` as shown, for
example) are recorded in the backup list 200A.
[0086] The `acceptance date and time` is information indicating the
date and time (or permitted time slot) when the backup destination
server 6A is granted access to the backup source server 3, and is
expressed in predetermined units
(year/month/day/hour/minutes/seconds, for example). The acceptance
date and time is allocated automatically by the backup request unit
12, for example, but may be established manually by a predetermined
user (operations manager, for example). The backup request unit 12
is able to avoid a concentration of the load resulting from the
backup processing on the backup destination servers 6A to 6C by
varying the respective acceptance date and time of the backup lists
200A to 200C at fixed time intervals (a time interval that is
presumed necessary in order for the backup destination servers 6A
to 6C to acquire one or more predetermined backup target files from
the backup source server 3, for example). Further, the time
required in order to acquire one or more predetermined backup
target files can be estimated from the total of the data size of
the backup target files, for example.
[0087] The `host name` is information indicating the name of the
backup destination server 6A.
[0088] The `file list` expresses information relating to one or
more backup target files classified as backed up to the backup
destination server 6A (the file name, path name, data size, and so
forth, of each file, for example) in list format.
[0089] The other backup lists 200B and 200C are substantially the
same as the backup list 200A. The backup request unit 12 creates
the backup lists 200A to 200C based on the flow described
below.
[0090] FIG. 7 is an image diagram of the flow of the processing of
the backup request unit 12.
[0091] As shown in FIG. 7, the backup request unit 12 collates the
classification result data D21 that is output by the data
characteristic classification unit 11, and pre-prepared backup
destination mapping information D22, and thus obtains data D23 that
is produced by converting a data characteristic ID in the
classification result data D21 into a backup destination host name
(backup destination server name). Next, the backup request unit 12
sorts sets of file names and host names recorded in this data D23
by the host names, and thus converts the data D23 into data D24 in
which the sets of file names and host names recorded in this data
D23 are sorted by the host names. The backup request unit 12 then
divides up and outputs this data D24 into files for each host name,
and creates the backup lists 200A to 200C corresponding to the
backup destination servers 6A to 6C respectively by adding the
above-mentioned acceptance date and time to each output file
(further, the backup lists 200A to 200C may be divided into even
smaller files, in which case the acceptance date and time is added
to each further divided file).
[0092] The backup request unit 12 transmits the backup lists 200A
to 200C so created to the corresponding backup destination servers
6A to 6C. Accordingly, the backup destination servers 6A to 6C
assign discrimination information (hereinafter `backup
discrimination information`) to the received backup lists 200A to
200C and transmit this backup discrimination information to the
backup source server 3. The backup source server 3 receives backup
discrimination information from each of the backup destination
servers 6A to 6C and the backup request unit 12 creates restore
information for recovering backup target files on the basis of the
backup discrimination information (the restore information as well
as the restoration processing that employs this information will be
described in detail subsequently).
[0093] Upon receiving a download request (described subsequently)
from the backup destination servers 6A to 6C, the backup request
unit 12 stores the transmitted backup lists 200A to 200C in
predetermined storage regions (predetermined storage regions in the
backup source server 3 or backup source storage device 4, for
example) in order to perform a validity check on the date and time
a request is received and to back up one or more predetermined
backup target files in the backup destination servers 6A to 6C
constituting the request source.
[0094] Let us refer to FIG. 2 once again. The download acceptance
unit 13 accepts backup target file download (transfer) requests
from the backup destination servers 6A to 6C, and, in the event of
a request, checks whether the date and time when the request was
received are valid. More specifically, in a case where the download
acceptance unit 13 receives a download request from the backup
destination server 6A, for example, the download acceptance unit 13
judges whether there is a complete or substantial match between
this date and time and a date and time that is designated in
advance by the backup source server 3 with respect to the backup
destination server 6A (that is, the acceptance date and time
written in the backup list 200A that is output by the backup
request unit 12). In the event of such a match, the download
acceptance unit 13 reads one or more backup target files that have
one or more file names written in the backup file 200A from a
predetermined location (the backup source storage device 4, for
example), and transmits these backup target files to the backup
destination server 6A that is the source of the download request.
On the other hand, if no such match exists, the download acceptance
unit 13 performs predetermined processing, i.e. communicates an
error to the backup destination server 6A, for example. Further,
the above-mentioned `substantial match` means that the difference
between the current date and time when the download request is
received and the acceptance date and time lies within a
predetermined error range, for example, and this predetermined
error range may be common to all the backup lists or vary from one
backup list to the next. In addition, the predetermined error range
may be varied by a predetermined user or may be fixed so as to be
unchangeable. Further, the predetermined error range may be stored
in a predetermined storage device separately from the backup list
or may be described in the backup list.
[0095] The restore unit 14 restores a backup target file on the
basis of the restore information created by the backup request unit
12 (described in detail subsequently with respect to the restore
processing).
[0096] Each application with which the backup source server 3 is
equipped was described above. Next, the backup destination server
6A will be described representatively for the backup destination
servers 6A to 6C with reference to FIG. 2 (further, although the
backup destination server 6A is illustrated representatively in
FIG. 2, the other backup destination servers 6B and 6C are also
able to communicate with the backup source server 3).
[0097] The backup destination server 6A comprises an operating
system (OS) 20 and the backup request acceptance unit 21 as
application software above this OS.
[0098] The backup request acceptance unit 21 receives the backup
list 200A from the backup source server 3 and stores this list in a
predetermined storage region (a predetermined storage region in the
backup destination server 6A or backup destination storage device
5A, for example). The backup request acceptance unit 21 then
generates backup discrimination information for this backup on the
basis of the backup list 200, and stores this information in a
predetermined storage region. Then, after running a process to
perform backup processing, the backup request acceptance unit 21
transmits the stored backup discrimination information to the
backup source server 3. Incidentally, the backup process is in a
standby state until the current date and time reaches the
acceptance date and time listed in the received and stored backup
list 200A (until the current date and time falls within the range
of a time slot when the acceptance date and time is expressed by
this time slot). When the current date and time reaches the
acceptance date and time of the backup list 200A, the backup
request acceptance unit 21 runs a backup process, issues a download
(transfer) request to the download acceptance unit 13 of the backup
source server 3, and creates an archive file that has the stored
backup discrimination information.
[0099] FIG. 8 shows the constitution of an archive file created by
the backup request acceptance unit 21.
[0100] For example, as is shown, stored in the archive file for the
backup list 200A are: backup discrimination information generated
for the backup list 200A, the entry number of backup target files
(that is, the number of backup target files stored in the archive
file), and backup target information in an amount corresponding to
the entry number (such as the data size, path within the backup
source server 3, and body (file itself), of each file, for
example).
[0101] When the backup request acceptance unit 21 shown in FIG. 2
downloads one or more backup target files recorded in the backup
list 200A from the backup source server 3 in response to the
download request, the backup request acceptance unit 21 stores
these backup target files in the archive file. Once the processing
to store the backup target files in the archive file is complete,
the backup request acceptance unit 21 stores the archive file
containing the backup target files in the backup destination
storage device 5A.
[0102] The flow of the processing of each application above will
now be described below by using a flowchart.
[0103] FIG. 9 is a flowchart showing the flow of the processing of
the data characteristic classification unit 11 that the backup
source server 3 comprises.
[0104] A predetermined user (operations manager, for example)
inputs a backup target directory (or a directory with the backup
target file, for example) to the backup source server 3 (step S1).
Further, the data characteristic classification unit 11 reads (S2)
the data characteristic classification definition information (see
FIG. 3) that has been preset and stored.
[0105] Next, the data characteristic classification unit 11
searches for directories and files contained in the directory that
is input in S1 (that is, on a level below the directory), and, if
the sought directories and files are present (YES in S3), acquires
metadata for all these files and directories (and/or actual data)
(S4).
[0106] Next, the data characteristic classification unit 11
collates (S5) metadata (and/or actual data) for the files (and
directories) acquired in S4 and data characteristic classification
definition information read in S2, performs classification based on
the data characteristics of the backup target files by capturing
the data characteristic IDs corresponding to the backup target
files and then associating these data characteristic IDs with the
files, and outputs (S6) the classification result data representing
the classification results (see FIG. 4), and stores this data in a
predetermined storage region. For example, the data characteristic
classification unit 11 may read a plurality of files in the
directory that was input in S1 one by one, and then repeatedly
execute S4 to S6. That is, the data characteristic classification
unit 11 performs S4 to S6 by reading out a certain single file from
the plurality of files in the directory input in S1, and then
performs S4 to S6 by reading out another single file, and may
repeat this processing until it is complete for all these plural
files.
[0107] Further, as a result of such classification processing, the
one or more backup target files retrieved in S3 are classified
according to a predetermined standard, such as at least one
standard among (A) to (C) and (a) to (f) mentioned earlier, for
example, based on the file data characteristics. That is, one or
more characteristic ID data items is (are) assigned to each backup
target file on the basis of at least one item among: the number of
common users of the file, special features common to the common
users, an extension, a keyword, and the presence or absence of
access restriction information such as an ACL, and the presence or
absence of encryption, for example.
[0108] Further, in this classification processing, depending on the
content of metadata (or actual data) of a backup target file
(and/or directory), a plurality of conditions expressed by a rule
body are sometimes satisfied, in which case a plurality of data
characteristic IDs are assigned to one backup target file. Further,
in a case where, in the mapping information, two or more server
information items (host names, for example) correspond with one
data characteristic ID, one backup target file is backed up to two
or more servers.
[0109] When the backup target is designated, the serial flow above
can also be performed with predetermined timing, such as
immediately after the designation, for example, or can be performed
at fixed or irregular intervals after the designation. In the
latter case, for example, if the user designates a pre-prepared
desired directory as the backup target and stores a file in this
desired directory, the classification of the file stored in the
desired directory is performed automatically at fixed intervals or
with other predetermined timing.
[0110] FIGS. 10 and 11 are flowcharts showing the flow of the
processing of the backup request unit 12.
[0111] When the backup request unit 12 receives a backup request
from outside (the operations manager, for example), for example,
with predetermined timing, the classification result data that is
output by the data characteristic classification unit 11 is read
from a predetermined storage region (S11) as shown in FIG. 10.
[0112] Next, the backup request unit 12 reads the pre-prepared
backup destination mapping information (S12).
[0113] The backup request unit 12 then sets the counter value at
`0` (S13), and compares this value with the number of files
recorded in the classification result data (S14). The backup
request unit 12 performs the processing of (S15) to (S18) below
until the counter value equals the number of files of the backup
target files recorded in the classification result data (NO in
S14).
[0114] (S15) The backup request unit 12 acquires the data
characteristic ID corresponding with the file name (or path name)
of the target recorded in the classification result data.
[0115] (S16) The backup request unit 12 references the backup
destination mapping information to acquire the host name
corresponding with the data characteristic ID acquired in S15.
[0116] (S17) The backup request unit 12 associates the host name
acquired in S16 with the file name of the target in S15, renders a
set of the file name and the host name one record, and outputs same
to a predetermined temporary file (the data file D23 shown in FIG.
8, for example).
[0117] (S18) The backup request unit 12 increments the counter
value by one.
[0118] Once the counter value reaches the file number recorded in
the classification in result data as a result of the above
processing of (S15) to (S18) (YES in S14), the backup request unit
12 sorts the one or more records recorded in the temporary file by
the host names (S19).
[0119] Next, on the basis of the host name, the backup request unit
12 divides up the temporary file whose records have been sorted by
the host name. That is, the backup request unit 12 performs
division to produce the same number of files as the types of host
names (that is, the backup destination servers 6A to 6C) recorded
in the temporary file, and creates and outputs (S20) the backup
lists 200A to 200C corresponding with the backup destination
servers 6A to 6C by recording the acceptance date and time in the
files obtained by this division.
[0120] Next, as shown in FIG. 11, the backup request unit 12
performs the following processing on all the backup lists 200A to
200C.
[0121] That is, first of all, the backup request unit 12 captures
(S25) the backup destination servers 6A to 6C by acquiring the host
names (backup destination server names) from the backup lists 200A
to 200C.
[0122] The backup request unit 12 then transmits (S26) each of the
backup lists 200A to 200C to the backup destination servers 6A to
6C thus captured in S25. The backup request unit 12 also stores
these backup lists 200A to 200C in a predetermined storage
region.
[0123] Thereafter, the backup request unit 12 receives (S27) a
response that includes the above-mentioned backup discrimination
information from the backup destination servers 6A to 6C. The
backup request unit 12 then renders the backup discrimination
information included in the response and information (host name,
for example) relating to the backup destination server constituting
the information transmission source a set, and outputs this set
(S28) to a predetermined file (for example, a restore file
described subsequently).
[0124] FIG. 12 is a flowchart showing the flow of the processing of
the download acceptance unit 13.
[0125] When the download acceptance unit 13 receives (YES in S31) a
download request including the host name of the server 6A from the
backup destination server 6A, for example, the download acceptance
unit 13 acquires (S32) the acceptance date and time and the host
name from all the file lists 200A to 200C output by the backup
request unit 12.
[0126] The download acceptance unit 13 compares the host name and
the current date and time included in the download request received
in S31 with the host name and acceptance date and time acquired in
S32, and thus judges whether a match exists (S33).
[0127] When such a match exists (YES in S33) as a result of the
judgment in S23, the download acceptance unit 13 reads out one or
more backup target files each having one or file names listed in
the backup list 200A from the backup source storage device 4 and
transmits (S34) the one or more backup target files thus read to
the backup destination server 6A that is the transmission source of
the download request.
[0128] When, on the other hand, no such match exists as a result of
S23, the download acceptance unit 13 transmits an error to the
backup destination server 6A (S35).
[0129] FIGS. 13 and 14 show the flow of the processing of the
backup request acceptance unit 21 of the backup destination server.
The backup destination server is described below as the backup
destination server 6A.
[0130] As shown in FIG. 13, the backup request acceptance unit 21
of the backup destination server 6A receives (S41) the backup list
200A from the backup request unit 12 of the backup source server 3
and stores the backup list 200A in a predetermined storage
region.
[0131] Next, the backup request acceptance unit 21 creates backup
discrimination information relating to the backup list 200A
(S42).
[0132] The backup request acceptance unit 21 then generates and
runs the backup process (S43).
[0133] Thereafter, the backup request acceptance unit 21 transmits
(S44) the backup discrimination information thus created in S42 to
the backup request unit 12 of the backup source server 3.
[0134] Thereafter, as shown in FIG. 14, when it is detected that
the current date and time has reached the acceptance date and time
listed in the backup list 200A (YES in S51), the backup request
acceptance unit 21 creates (S52) an archive file (see FIG. 8) with
the backup discrimination information created in S42 by means of
the backup process run in S43.
[0135] Next, the backup request acceptance unit 21 records (S53)
information relating to the backup lists 200 in the archive file.
For example, based on the backup lists 200, the backup request
acceptance unit 21 registers the number of file names recorded in
the backup list 200A as the entry number in the created archive
file and registers the path (path within the backup source server
3) of each file.
[0136] Next, the backup request acceptance unit 21 receives (YES in
S54, and S55) one or more backup target files each having one or
more file names written in the backup list 200A from the backup
source server 3 and stores the received backup target files in the
archive file (S56).
[0137] Once the backup request acceptance unit 21 has downloaded
all the backup target files and stored these files in an archive
file (NO in S54), the archive file is stored in the backup
destination storage device 5A (S57).
[0138] According to the embodiment above, data characteristic
classification definition information in which one or a plurality
of data characteristic IDs correspond with one or more data
characteristic types, and mapping information in which one, or two
or more backup destination server information items (server names,
for example) correspond with one or a plurality of data
characteristic IDs are prepared. Upon receiving a backup target
designation, the backup source server 3 sets metadata (and/or
actual data) for the designated files (and/or directories) with
predetermined timing, and, based on the above data characteristic
classification definition information, sets data characteristic IDs
(that is, data characteristic types) for the backup target files,
and, based on the set data characteristic IDs and mapping
information, determines the backup destination servers 6A to 6C of
the backup target files, before transmitting the backup target
files to the servers 6A to 6C so determined. Accordingly, even if
the data characteristic classification definition information and
mapping information (or, instead, information in which one, or two
or more backup destination server information items correspond with
one or more data characteristic types) are prepared, the designated
backup target is automatically backed up to the backup destination
matching the data characteristic type of the backup target on the
basis of the data characteristics of the backup target. That is,
backup processing, which is suited to the data characteristics
relating to the backup target, is performed by means of a method
that is simple for the user.
[0139] Further, according to the above embodiment, when there is no
match between the current date and time when the download request
is received from a certain backup destination server 6A and the
acceptance date and time allocated to the backup list 200A of the
server 6A, that is, even when a download request is received at a
date and time other than the predetermined acceptance date and
time, the backup source server 3 does not perform a backup of the
backup target file. Accordingly, unauthorized downloading of the
backup target file can be prevented before it takes place, whereby
the security of the backup target file can be raised.
[0140] Therefore, according to the embodiment above, the backup
discrimination information that the backup destination servers 6A
to 6C create upon receiving the backup lists 200A to 200C is used
by the backup source server 3 in order to recover the backup target
files written in the backup lists 200A to 200C. The backup
discrimination information corresponding with the backup lists 200A
to 200C may be any information as long as the backup source server
3 is able to obtain the backup target files written in the
corresponding backup list from the backup destination servers 6A to
6C. For example, the backup discrimination information can be
information including at least one of the backup destination server
name, the name of the backed up backup target file, and the data
size. In such a case, the backup source server 3 can inform any
backup destination server which file is to be stored by managing
such information.
[0141] When backup discrimination information is received from the
backup destination servers 6A to 6C, the backup source server 3
associates and records backup discrimination information
corresponding with each of the servers 6A to 6C with information
relating to a plurality of backup destination servers 6A to 6C
(host name, for example) in a predetermined restore file D30 shown
in FIG. 15, for example.
[0142] Then the backup source server 3 restores the backup target
file to the backup source storage device 4 as follows by using the
restore file D30.
[0143] FIG. 16 shows the flow of the restore processing of the
backup source server 3.
[0144] The backup source server 3 performs the processing of (S61)
to (S65) below with respect to all the servers 6A to 6C each having
all the host names recorded in the restore file D30. This
processing is described representatively for server 6A below.
[0145] (S61) The backup source server 3 connects to the backup
destination server 6A.
[0146] (S62) The backup source server 3 reads the backup
discrimination information for the server 6A constituting the
connection destination from the restore file D30, sets the storage
destination directory for the backup target file to be subsequently
acquired from the backup destination server 6A in the backup source
storage device 5, and acquires the path of this directory.
[0147] (S63) The backup source server 3 communicates the read
backup discrimination information to the backup destination server
6A and, based on this backup discrimination information, specifies
the archive file that stores the backup target file constituting
the recovery target to the server 6 and acquires the backup target
file from the specified archive file, whereby the acquired backup
target file is received from the backup destination server 6A.
[0148] (S64) Based on the path acquired in S62, the backup source
server 3 stores the backup target file received from the backup
destination server 6A in the directory set in S62.
[0149] (S65) The backup source server 3 breaks the connection with
the backup destination server 6A.
[0150] As a result of the above processing, the backup source
server 3 is able to restore one or more backup target files, which
have been backed up in the backup destination servers 6A to 6C
respectively, to the backup source storage devices 5.
[0151] A preferred embodiment of the present invention has been
described above but this embodiment is an example serving to
illustrate the present invention and is not intended to restrict
the scope of the present invention to this embodiment alone. The
present invention can also be implemented in a variety of other
forms.
[0152] For example, the backup request unit 12 is able to avoid a
concentration of the load resulting from the backup processing on
the backup destination servers 6A to 6C by varying the respective
acceptance date and time of the backup lists 200A to 200C at fixed
time intervals (a time interval that is presumed necessary in order
for the backup destination servers 6A to 6C to acquire one or more
predetermined backup target files from the backup source server 3,
for example). This acceptance date and time may be established
manually by the individual requesting the backup or may be
established automatically by the backup source server 3. When the
acceptance date and time are established automatically, the backup
source server 3 is able to capture the total data size of one or
more backed up backup target files for each of the backup
destination servers 6A to 6C, estimate the time required for the
backup on the basis of the data size, and schedule the acceptance
date and time on the basis of the estimated time, for example (the
acceptance date and time may be set in the order of the estimated
backup time starting with the shortest or longest time first, for
example).
[0153] In addition, for example, the backup destination servers 6A
to 6C may issue a download request immediately after receiving a
backup list from the backup source server 3. In this case, the
acceptance date and time need not be written in the backup list,
for example. Alternatively, when a download request is issued, the
download request may be issued once again at the acceptance date
and time listed in the backup list only when the communication
traffic is congested. Further, in this case, for example, the
backup source server 3 may transmit all the backup lists 200A to
200C to the backup destination servers 6A to 6C at the same time,
or may schedule the timing for transmitting the backup lists 200A
to 200C and perform transmission at another time. When a backup
destination server requests a download immediately after receiving
a backup list, the concentration of the load on the backup source
server 3 or network can be avoided by adjusting the timing for
transmitting the backup lists 200A to 200C. Further, the timing for
transmitting the backup lists may be scheduled on the basis of an
estimated time by capturing the total data size of one or more
backup target files for each of the backup destination servers 6A
to 6C, for example, and estimating the time required for a backup
on the basis of this data size (the transmission timing may be
brought forward for a shorter or longer estimated backup time, for
example).
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