Data acquisition of snapshots

Patent metadata

Field	Value
Publication number	US-12124336-B2
Application number	US-202318120445-A
Country	US
Kind code	B2
Filing date	Mar 13, 2023
Priority date	Aug 3, 2022
Publication date	Oct 22, 2024
Grant date	Oct 22, 2024

Abstract

In a storage system that acquires data from a storage system via a network, in the storage system, a snapshot 108 with respect to a predetermined volume is managed, the storage system includes a CPU, and the CPU is configured to receive an acquisition instruction of data of a first snapshot of the predetermined volume and acquire at least a part of data of a difference between the first snapshot and a second snapshot from the storage system when data of the second snapshot of the predetermined volume is acquired.

First claim

What is claimed is:

1. A data acquisition apparatus that acquires data from an external storage system via a network, wherein in the external storage system, a snapshot with respect to a predetermined volume is managed, the data acquisition apparatus comprising:
a processor; and a storage medium,
wherein the processor is configured to:
receive an acquisition instruction of data of a second snapshot of the predetermined volume, acquires the data of the second snapshot from the external storage system and stores the data of the second snapshot in the storage medium,
receive an acquisition instruction of data related to a whole area of a first snapshot of the predetermined volume,
inquire, of the external storage system, presence/absence of a difference between the first snapshot and the second snapshot, and
acquire data of the first snapshot related to a difference between the first snapshot and the second snapshot from the external storage system, based on a difference related to a result of the inquiry of the presence/absence of the difference, when data of the second snapshot of the predetermined volume is already acquired, and stores it in the storage medium.

2. The data acquisition apparatus according to claim 1 ,
further comprising: a virtual volume configured by software defined storage (SDS) and a host,
wherein the data stored in the virtual volume exists on a storage device within the SDS or within a snapshot stored in the external storage system,
wherein the external storage system stores the first snapshot and the second snapshot,
wherein in a case where the SDS acquires the data of the first snapshot, and when data of the second Snapshot is further acquired, inquire of address information indicating a data difference among the first snapshot and the second snapshot and store only differential data on the storage device based on the address information, and
wherein the processor is configured to inquire of the external storage system presence/absence of the difference between the first snapshot and the second snapshot when switching a snapshot to be provided from the second snapshot to the first snapshot.

3. A data acquisition apparatus that acquires data from an external storage system via a network, wherein in the external storage system, a snapshot with respect to a predetermined volume is managed, the data acquisition apparatus comprising:
a processor, the processor configured to:
receive an acquisition instruction of data of a first snapshot of the predetermined volume,
inquire, of the external storage system, presence/absence of a difference between the first snapshot and the second snapshot when data of the second snapshot of the predetermined volume is already acquired, and
acquire at least a part of data of the difference between the first snapshot and a second snapshot from the external storage system, based on an inquiry result of the presence/absence of the difference,
manage a read presence/absence of data for each of a plurality of predetermined areas of the second snapshot acquired by the data acquisition apparatus,
inquire the external storage system of the presence/absence of the difference of data of the first snapshot by giving priority to a read presence area of the second snapshot over a read absence area, when an acquisition instruction of the data of the first snapshot of the predetermined volume is received, and
acquire difference data corresponding to the read presence area of the second snapshot, which is data of the first snapshot, from the external storage system, in priority.

4. The data acquisition apparatus according to claim 3 ,
wherein, when difference data from the first snapshot in all read presence areas of the second snapshot is acquired from the external storage system, the processor is configured to respond to a request source of the acquisition instruction of data of the first snapshot.

5. The data acquisition apparatus according to claim 3 ,
wherein, after difference data in all read presence areas of the second snapshot is acquired, the processor is configured to inquire the external storage system of the presence/absence of the difference from data of the first snapshot in a read absence area of the second snapshot, and
acquire difference data corresponding to the read absence area of the second snapshot, if any, from the external storage system.

6. The data acquisition apparatus according to claim 3 ,
wherein the processor does not acquire difference data corresponding to a read absence area of the second snapshot, from the external storage system.

7. The data acquisition apparatus according to claim 3 ,
wherein, in case of receiving a read request to the data of the first snapshot, the processor is configured to:
return the acquired data to the read request source, when data of a target area of the read request is already acquired, and acquire data of the target area of the read request of the first snapshot from the external storage system and return the data to the read request source, when data of the target area of the read request is not acquired.

8. The data acquisition apparatus according to claim 1 ,
wherein the processor is configured to reflect the acquired difference data to a volume that stores data of a creation source of the second snapshot, and
create a snapshot of the volume.

9. The data acquisition apparatus according to claim 1 ,
wherein the network is a wide area network.

10. The data acquisition apparatus according to claim 2 ,
wherein the processor is configured to:
upon receiving a switching instruction of switching a snapshot destination of storing data of the virtual volume from the first snapshot to the second snapshot, switch a snapshot destination of storing data of the virtual volume from the first snapshot to the second snapshot,
inquire, of the external storage system, address information indicating a data difference between the first snapshot and the second snapshot, and
update the virtual volume with the differential data acquired from the address information.

11. The data acquisition apparatus according to claim 1 , further comprising a plurality of virtual volumes,
wherein the external storage system includes a plurality of snapshots, including the first snapshot and the second snapshot.

12. The data acquisition apparatus according to claim 10 ,
wherein after the switch of the snapshot destination, the host is accessible for input/output.

13. A data acquisition method by a data acquisition apparatus that acquires data from an external storage system via a network, wherein, in the external storage system, a snapshot with respect to a predetermined volume is managed, the method comprising:
receiving an acquisition instruction of data of a second snapshot of the predetermined volume, acquiring the data of the second snapshot from the external storage system and storing the data of the second snapshot in a storage medium of the data acquisition apparatus;
inquiring of the external storage system presence/absence of a difference between the first snapshot and the second snapshot;
receiving an acquisition instruction of data related to the whole area of a first snapshot of the predetermined volume, and
acquiring data of the first snapshot related to a difference between the first snapshot and a second snapshot from the external storage system, based on the difference related to the inquiry results when data of the second snapshot of the predetermined volume is already acquired, and stores it in the storage medium.

Assignees

• Hitachi Ltd

Inventors

• Hara Akihiro
• Yamamoto Takahiro
• Saito Hideo
• Suzuki Takanobu
• Deguchi Akira

Classifications

• G06F11/1464

  for networked environments · CPC title

• G06F16/128 Primary

  Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion (error detection or correction of the data by redundancy in operations or in hardware G06F11/14, G06F11/16) · CPC title

• G06F2201/84

  Using snapshots, i.e. a logical point-in-time copy of the data · CPC title

• G06F11/1456

  Hardware arrangements for backup · CPC title

• G06F11/3055

  Monitoring arrangements for monitoring the status of the computing system or of the computing system component, e.g. monitoring if the computing system is on, off, available, not available (error or fault processing without redundancy G06F11/0703; error detection or correction by redundancy in data representation G06F11/08; error detection or correction of the data by redundancy in operations G06F11/14; error detection or correction by redundancy in hardware G06F11/16) · CPC title