EP1148416A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Computer system and snapshot data management method
Assignee: Hitachi Ltd
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Filing: 2000-08-21
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Granted: —
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Expires: 2020-08-21
Abstract
Abstract A method of managing a snapshot data of a computer system provided with a computer and a storage subsystem coupled with the computer, and the computer system to which the method is applied are disclosed. The storage subsystem is provided with the duplicated first and second storage units. In the state in which they are duplicated, when a request to update data is issued to the first storage unit, the storage subsystem writes the same updated data onto the second storage unit. When an acquisition of the snapshot is requested by the computer at any time, the storage subsystem suspends the writing of the writing data for the first storage unit onto the second storage unit thereafter. When the writing of the data onto the first storage unit occurs, the computer holds the location of writing the data as differential information. When making the contents of the first storage unit and the second storage unit the same, the data written onto the first storage unit after the acquisition of the snapshot is requested is written onto the second storage unit.
Inventors
- 👤 Yasuyuki Hitachi Ltd. Intel.Prop.Group Mimatsu
- 👤 Naoto Hitachi Ltd. Intel.Prop.Group Matsunami
- 👤 Kenji Hitachi Ltd. Intel.Prop.Group Muraoka
- 👤 Takashi Hitachi Ltd. Intel.Prop.Group Oeda
- 👤 Ikuya Hitachi Ltd. Intel.Prop.Group Yagisawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 00:22
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1446; G06F11/1458; G06F11/1466; G06F2201/00; G06F2201/84; Y; Y10; Y10S; Y10S707/00; Y10S707/99951; Y10S707/99952; Y10S707/99953; Y10S707/99955
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
191 words
A method of managing snapshot information in a computer system
comprising a computer and a storage subsystem, which is coupled with
said computer, having two or more storage units, said method comprising
the steps of: holding, in said storage subsystem, duplicated data in a first
and a second storage units being correlated with each other in advance,
and writing data on both of said first and said second storage units, in
obedience to data writing requests from said computer; setting the mode of said storage subsystem to the mode for
acquiring said snapshot; executing, by said storage subsystem, write operation to write
data into said first storage unit in accordance with a write request issued
by said computer while said storage subsystem is in the mode for
acquiring said snapshot; holding, by said computer, the storage location of data to be
updated according to the write request issued after said setting step as
differential information; and setting the mode of said storage subsystem to the mode for
getting re-synchronized, and making contents of said first storage unit and
contents of said second storage unit the same based on said differential
information.
Claim 2
Dependent Claim
55 words
The method according to claim 1 further comprising a step of
writing, by said storage subsystem, the write data according to said
writing request into both of said first and said second storage units when
the write request designating said first storage unit is received while its
mode is in said mode for getting re-synchronized.
Claim 3
Dependent Claim
99 words
The method according to claim 1, wherein said making step
comprising the steps of: acquiring, by said computer, the location of the data being
updated according to the write request issued after the acquisition request
of said snapshot based on said differential information and reading out the
data stored in said location from said storage system; requesting, by said computer, said storage subsystem to write
the data read out based on said differential information; and storing, in response to said request, the data read out based on
said differential information in said second storage unit by said storage
subsystem.
Claim 4
Dependent Claim
80 words
The method according to claim 1, wherein said making step
comprising the steps of: acquiring, based on said differential information, the location of
data which has been updated by the write request issued after the
acquisition request of snapshot; requesting said storage subsystem to copy the data with
designating the acquired location of said data; and copying, by said storage subsystem, the data in the location
designated by said request from said first storage unit to said second
storage unit.
Claim 5
Dependent Claim
33 words
The method according to claim 1, wherein said making step
includes a step of setting the mode in which the access designating said
second storage unit is prohibited in response to said instruction.
Claim 6
Dependent Claim
38 words
The method according to claim 1, further comprising a step of
setting a mode of said second storage unit to prohibit writing write data
into said second storage unit in response to the request for acquiring said
snapshot.
Claim 7
Dependent Claim
40 words
The method according to claim 1, further comprising a step of
copying the data being held in said second storage unit to said third
storage unit, and wherein said making step is performed after the
completion of said copying step.
Claim 8
Dependent Claim
22 words
The method according to claim 7, wherein said copying step is
performed by another computer with which said storage subsystem is
coupled.
Claim 9
Dependent Claim
168 words
A computer system comprising: a computer; and a storage subsystem being coupled with said computer, said
storage subsystem including a first storage unit, a second storage unit,
and a control unit controlling said first and said second storage units,
where said control unit writes the write data accompanying said write
request into both of said first and second storage units in accordance with
the request, from said computer, to write data into said first storage unit
when said control unit is set in the synchronized mode by said computer,
and prohibits writing data on said second storage unit when it is set in the
snapshot mode by said computer; and said computer including means which selectively sets a
operation mode including said synchronized mode and said snapshot mode
to said storage subsystem, and means which holds the differential
information indicating data writing location according to said writing
request when the data writing request is issued to said storage subsystem
while said storage subsystem is in a snapshot mode.
Claim 10
Dependent Claim
55 words
The computer system according to claim 9, wherein said operating
mode includes the re-synchronized mode for making contents of said first
storage unit and said second storage unit the same, and said control unit
prohibits the reading out processing from said second storage unit when it
is set in the re-synchronized mode by said computer.
Claim 11
Dependent Claim
69 words
A computer system according to claim 10, wherein said computer
has means for acquiring, based on said differential information, a storage
location in said first storage unit to which data was written when said
storage subsystem was in the snapshot mode, reading out the data from
the acquired storage location in said first storage unit, and issuing write
request to write the read out data into said storage location.
Claim 12
Dependent Claim
81 words
A computer system according to claim 10, wherein said computer
acquires, based on said differential information, the storage location in
said first storage unit to which data was written when said storage unit
was in the said snapshot mode, and instructs said storage subsystem to
copy data held in said storage location, and wherein said control unit
copies the data held in said storage location in said first storage unit to
said second storage unit in response to said copying instruction.
Claim 13
Dependent Claim
27 words
A computer system according to claim 10, wherein said control unit
rejects read request designating said second storage unit when it is set in
said re-synchronized mode.
Claim 14
Dependent Claim
27 words
A computer system according to claim 9, wherein said control unit
rejects write request designating said second storage unit when it is set in
said snapshot mode.
Claim 15
Dependent Claim
37 words
A computer system according to claim 9, further having a storage
device and wherein said computer copies the contents of said second
storage unit to said storage device when said storage subsystem is in said
snapshot mode.
Claim 16
Dependent Claim
61 words
A computer system according to claim 9, further comprising: a storage device; and a backup computer being communicably coupled with said
computer; wherein said backup computer receives a notification that said
storage subsystem is in said snapshot mode from said computer and copies
the data held in said second storage unit to said third storage unit in
response to said notification.
Claim 17
Dependent Claim
155 words
A computer system, comprising: a storage subsystem including a first storage unit, a second
storage unit, and a control unit controlling said first and said second
storage units; and a computer having: means for selectively setting operating mode, which includes a
synchronized mode and a snapshot mode, to said storage subsystem, means for receiving write request to said storage subsystem
issued by an application program running on the computer, means for issuing a write request with designating a first
identifier discriminating a pair of said first and said second storage units
when said storage subsystem is set in said synchronized mode by said
setting means for said storage subsystem, and for issuing write request
designating a second identifier discriminating said first storage unit when
said storage subsystem is set in said snapshot, and means for acquiring and holding differential information
indicating location of said first storage unit designated by write request
designating said first identifier.
Claim 18
Dependent Claim
37 words
A computer system according to claim 17, wherein said control unit
writes data accompanying said writing request on both of said first and
said second storage units in response to the write request designating said
first identifier.
Claim 19
Dependent Claim
65 words
A computer system according to claim 18, wherein said operation
mode includes the re-synchronized mode which makes the contents of said
first storage unit and said second storage unit the same, and said issuing
means issues the write request designating said first identifier in
obedience to write request from a program which runs on said computer
when said storage subsystem is in said re-synchronized mode.
References Cited (Backward Citations)
No citation records indexed.
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