Method, apparatus and computer program product for managing data storage in data storage systems

Patent metadata

Field	Value
Publication number	US-10776205-B2
Application number	US-201815966031-A
Country	US
Kind code	B2
Filing date	Apr 30, 2018
Priority date	Jan 30, 2018
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

Techniques are disclosed for managing data storage. In one embodiment, the techniques determine one or more RAID extents having a disk extent supported by an extent of storage on a storage device in an inoperative state. Each of the RAID extents contains a respective set of disk extents allocated to that RAID extent and each disk extent is supported by an extent of storage on a storage device of the set of storage devices. The techniques also comprise evaluating a set of values, wherein each value indicates, for a corresponding pair of storage devices from the set of storage devices, a number of RAID extents which contain disk extents belonging to both storage devices of the pair. The techniques also comprise selecting, based on the said evaluation and for each of the one or more RAID extents, a free disk extent for facilitating rebuild of that RAID extent, wherein the said free disk extent is supported by an extent of storage of one of the set of storage devices other than one of the storage devices associated with that RAID extent.

First claim

What is claimed is:

1. A method, comprising:
detecting an inoperative state relating to a storage device of a set of storage devices of a data storage system;
in response to detecting the inoperative state, determining one or more RAID extents having a disk extent supported by an extent of storage on the storage device associated with the inoperative state, wherein each of the RAID extents contains a respective set of disk extents allocated to that RAID extent and each disk extent is supported by an extent of storage on a storage device of the set of storage devices;
evaluating a set of values, wherein each value indicates, for a corresponding pair of storage devices from the set of storage devices, a number of RAID extents which contain disk extents belonging to both storage devices of the pair;
based on the said evaluation, selecting, for each of the one or more RAID extents, a free disk extent supported by an extent of storage of one of the set of storage devices other than one of the storage devices associated with that RAID extent; and
rebuilding the one or more RAID extents by utilizing the free disk extents selected for the respective RAID extents to replace the disk extents supported by the storage device associated with the inoperative state;
wherein each of the one or more RAID extents requires a free disk extent from one of the set of storage devices not associated with that RAID extent to facilitate rebuild of that RAID extent, and
wherein the said evaluating comprises:
for each of the one or more RAID extents:
calculating one or more scores in connection with one or more possible new configurations for the RAID extent that include disk extents from the operative storage devices of the RAID extent and one of the set of storage devices not associated with the RAID extent, wherein the one or more scores are calculated by summing values from the set of values that describe the one or more possible new configurations for the RAID extent;
identifying a minimum score from the said one or more scores, wherein the minimum score is associated with one of the one or more possible new configurations; and
based on the minimum score, selecting the storage device associated with the one of the one or more possible new configurations to provide the free disk extent to the RAID extent.

2. The method as claimed in claim 1 , wherein the said evaluating is performed in accordance with a neighborhood matrix that includes the values for each pair of storage device of the set of storage devices.

3. The method as claimed in claim 2 , wherein the neighborhood matrix includes N rows and N columns and wherein each entry (I, J) of the neighborhood matrix located at row I, column J denotes a count of how many times storage device I has neighbored storage device J in RAID extents such that the two storage devices I and J are neighbors with each other each time a disk extent from storage device I and a disk extent from storage device J are included in the same RAID extent.

4. The method as claimed in claim 1 , wherein the values are weighted based on the capacity of a storage device of the set of storage devices.

5. The method as claimed in claim 1 , wherein the values are weighted based on the capacity of a typical storage device of the set of storage devices and the capacity of the pair of storage devices associated with the value.

6. An apparatus, comprising:
memory; and
processing circuitry coupled to the memory, the memory storing instructions which, when executed by the processing circuitry, cause the processing circuitry to:
detect an inoperative state relating to a storage device of a set of storage devices of a data storage system;
in response to detecting the inoperative state, determine one or more RAID extents having a disk extent supported by an extent of storage on the storage device associated with the inoperative state, wherein each of the RAID extents contains a respective set of disk extents allocated to that RAID extent and each disk extent is supported by an extent of storage on a storage device of the set of storage devices;
evaluate a set of values, wherein each value indicates, for a corresponding pair of storage devices from the set of storage devices, a number of RAID extents which contain disk extents belonging to both storage devices of the pair;
based on the said evaluation, select, for each of the one or more RAID extents, a free disk extent supported by an extent of storage of one of the set of storage devices other than one of the storage devices associated with that RAID extent; and

rebuild the one or more RAID extents by utilizing the free disk extents selected for the respective RAID extents to replace the disk extents supported by the storage device associated with the inoperative state;
wherein each of the one or more RAID extents requires a free disk extent from one of the set of storage devices not associated with that RAID extent to facilitate rebuild of that RAID extent, and
wherein the said evaluating comprises:
for each of the one or more RAID extents:
calculating one or more scores in connection with one or more possible new configurations for the RAID extent that include disk extents from the operative storage devices of the RAID extent and one of the set of storage devices not associated with the RAID extent, wherein the one or more scores are calculated by summing values from the set of values that describe the one or more possible new configurations for the RAID extent;
identifying a minimum score from the said one or more scores, wherein the minimum score is associated with one of the one or more possible new configurations; and
based on the minimum score, selecting the storage device associated with the one of the one or more possible new configurations to provide the free disk extent to the RAID extent.

7. The apparatus as claimed in claim 6 , wherein the said evaluating is performed in accordance with a neighborhood matrix that includes the values for each pair of storage device of the set of storage devices.

8. The apparatus as claimed in claim 7 , wherein the neighborhood matrix includes N rows and N columns and wherein each entry (I, J) of the neighborhood matrix located at row I, column J denotes a count of how many times storage device I has neighbored storage device J in RAID extents such that the two storage devices I and J are neighbors with each other each time a disk extent from storage device I and a disk extent from storage device J are included in the same RAID extent.

9. The apparatus as claimed in claim 6 , wherein the values are weighted based on the capacity of a storage device of the set of storage devices.

10. The apparatus as claimed in claim 6 , wherein the values are weighted based on the capacity of a typical storage device of the set of storage devices and the capacity of the pair of storage devices associated with the value.

11. A computer program product having a non-transitory computer readable medium which stores a set of instructions, the set of instructions, when carried out by processing circuitry, causing the processing circuitry to perform a method of:
detecting an inoperative state relating to a storage device of a set of storage devices of a data storage system;
in response to detecting the inoperative state, determining one or more RAID extents having a disk extent supported by an extent of storage on the storage device associated with the inoperative state, wherein each of the RAID extents contains a respective set of disk extents allocated to that RAID extent and each disk extent is supported by an extent of storage on a storage device of the set of storage devices;
evaluating a set of values, wherein ea

Assignees

• Emc Ip Holding Co Llc

Inventors

• Li Wayne Weihua
• Gao Jian
• Kang Jamin
• Wang Sheng
• Ma Charles Chun

Classifications

• G06F11/1092 Primary

  Rebuilding, e.g. when physically replacing a failing disk · CPC title

• G06F3/0689

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

• G06F3/0604

  Improving or facilitating administration, e.g. storage management · CPC title

• G06F3/0629

  Configuration or reconfiguration of storage systems · CPC title

• G06F3/0619

  in relation to data integrity, e.g. data losses, bit errors · CPC title