Storage system, storage management method, and storage medium

Patent metadata

Field	Value
Publication number	US-2016283162-A1
Application number	US-201615060842-A
Country	US
Kind code	A1
Filing date	Mar 4, 2016
Priority date	Mar 24, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

Provided is a storage system ( 1200 ) including a first volume providing a storage area, a second volume providing another storage area including a difference from the first volume, and a volume management unit releasing an area allocated to a second specific partial storage area in a storage area in a storage device allocated to the second volume when accepting a delete request for specific data, in accordance with a result of confirmation of sameness between data included in the second specific partial storage area and data included in a first specific partial storage area. The second specific partial storage area is a partial storage area in the second volume including the specific data. The first specific partial storage area is a partial storage area in the first volume and associated with the second specific partial storage area.

First claim

1 . A storage system comprising:
a first volume configured to provide a storage area; a second volume configured to provide another storage area including a difference from the first volume; and a volume management unit configured to release an area allocated to a second specific partial storage area in a storage area in a storage device allocated to the second volume when accepting a delete request for specific data, based at least in part on a result of confirmation of sameness between data included in the second specific partial storage and data included in a first specific partial storage area, the second specific partial storage area being a partial storage area in the second volume including the specific data, the first specific partial storage area being a partial storage area in the first volume and being associated with the second specific partial storage area.

2 . The storage system according to claim 1 , wherein the volume management unit releases the area allocated to the second specific partial storage area in the storage area in the storage device, when data included in the second specific partial storage area that includes the specific data, and data included in the first specific partial storage area that is associated with the second specific partial storage area, are identical.

3 . The storage system according to claim 1 , wherein the volume management unit:
determines whether or not the data included in the second specific partial storage area are updated from the data included in the first specific partial storage area associated with the second specific partial storage area, when accepting the delete request; confirms sameness between the data included in the second specific partial storage area and the data included in the first specific partial storage area associated with the second specific partial storage area, when the data included in the second specific partial storage area are determined as updated data, as a result of the confirmation; and, releases the area allocated to the second specific partial storage area in the storage device, when the data included in the partial storage areas are determined to be identical.

4 . The storage system according to claim 3 , wherein, when accepting the delete request, the volume management unit:
determines whether or not data included in the second specific partial storage area are updated, by referring second volume management information including difference validity information, that indicates, for each of one or more partial storage areas included in the second volume, whether or not data included in the partial storage area are updated from data included in the partial storage area that is included in the first volume and is associated with the partial storage area included in the second volume; confirms sameness between the data included in the second specific partial storage area and the data included in the first specific partial storage area associated with the second specific partial storage area, when the second specific partial storage area is determined to be updated; and, releases the area allocated to the second specific partial storage area in the storage device, and sets information, indicating that data are not updated, to the difference validity information related to the second specific partial storage area, when data included in the partial storage areas are determined to be identical.

5 . The storage system according to claim 4 , wherein
the second volume management information includes difference check request information indicating, for each of one or more partial storage areas included in the second volume, whether or not the sameness needs to be determined between data included in the partial storage area included in the second volume and data that is included in the partial storage area in the first volume and is associated with the storage area included in the second volume, and the volume management unit:
sets information, indicating that determination of sameness is necessary, to the difference check request information related to the second specific partial storage area, when data included in the second specific partial storage area are determined to be updated, in accordance with the difference validity information related to the second specific partial storage area, at a point in time of accepting the delete request; and
confirms sameness between data included in the second specific partial storage area and data included in the first specific partial storage area associated with the second specific partial storage area, at a point in time later than the point in time of accepting the delete request, when information, indicating that determination of sameness is necessary, is set to the difference check request information.

6 . The storage system according to claim 3 , wherein the volume management unit determines, when determined that data included in the second specific partial storage area are updated, sameness between data that are included in the second specific partial storage area and data that are included in the first specific partial storage area, by comparing a check code generated from the data included in the second specific partial storage area with a check code generated from the data included in the first specific partial storage area associated with the second specific partial storage area, the check code being information that enables determining of whether or not the data and other data are identical.

7 . The storage system according to claim 6 , wherein the volume management unit determines sameness between data included in the second specific partial storage area and data included in the first specific partial storage area, when determined that the check code generated from the data included in the second specific partial storage area and the check code generated from the data included in the first specific partial storage area associated with the second specific partial storage area are identical, by further comparing the whole of the data included in the second specific partial storage area with the whole of the data included in the first specific partial storage area.

8 . The storage system according to claim 1 , wherein the volume management unit:
confirms sameness between data included in the second specific partial storage area and data included in the first specific partial storage area associated with the second specific partial storage area; and, sets a specific value to an area allocated to the second specific partial storage area in the storage device, when determined that the data are identical.

9 . A storage management method comprising:
accepting a delete request for specific data included in a storage including a first volume providing a storage area and a second volume providing a storage area including a difference from the first volume; and releasing an area allocated to a second specific partial storage area in a storage area in a storage device allocated to the second volume, based at least in part on a result of confirmation of sameness between data included in the second specific partial storage area and data included in a first specific partial storage area, the second specific partial storage area being a partial storage area in the second volume including the specific data, the first specific partial storage area being a partial storage area in the first volume and being associated with the second specific partial area.

10 . A non-transitory computer-readable storage medium recorded with a computer program, the computer program causing a computer to execute:
processing of accepting a delete request for specific data included in a storage including a first volume

Assignees

• Nec Corp

Inventors

• Inagaki Tomokazu

Classifications

• G06F3/0673

  Single storage device · CPC title

• G06F3/0652 Primary

  Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket · CPC title

• G06F3/0608

  Saving storage space on storage systems · CPC title

• G06F3/0689

  Disk arrays, e.g. RAID, JBOD · CPC title