Restoring a volume in a storage system

• US 10,013,317 B1
• Filed: 10/12/2016
• Issued: 07/03/2018
• Est. Priority Date: 01/10/2013
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Pure Storage, Inc.
• Inventors: Colgrove, John, Miller, Ethan, Hayes, John, Sandvig, Cary, Golden, Christopher, Cao, Jianting
• Primary Examiner(s): Butler, Sarai E
• Application Number:
  US15/291,373
• Time in Patent Office: 629 Days
• Field of Search: 714 15
• CPC Class Codes: G06F 16/1748 De-duplication implemented within the file system, e.g. based on file segments de-duplication techniques in storage systems for the management of data blocks G06F3/0641
• CPC Class Codes: G06F 16/23 Updating
• CPC Class Codes: G06F 2212/1008 Correctness of operation, e.g. memory ordering
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/1044 Space efficiency improvement
• CPC Class Codes: G06F 2212/154 Networked environment
• CPC Class Codes: G06F 2212/163 Server or database system
• CPC Class Codes: G06F 2212/261 Storage comprising a plurality of storage devices
• CPC Class Codes: G06F 2212/263 Network storage, e.g. SAN or NAS
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0614 Improving the reliability of storage systems
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0626 Reducing size or complexity of storage systems
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0644 : Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/065 : Replication mechanisms
• CPC Class Codes: G06F 3/0652 : Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0655 : Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0664 : at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0665 : at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0667 : at data level, e.g. file, record or object virtualisation
• CPC Class Codes: G06F 3/067 : Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0671 : In-line storage system
• CPC Class Codes: G06F 3/0673 : Single storage device
• CPC Class Codes: G06F 3/0683 : Plurality of storage devices
• CPC Class Codes: G06F 3/0685 : Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 3/0689 : Disk arrays, e.g. RAID, JBOD

Abstract

A system and method for performing search optimization operations. In order to optimize lookups for received data requests, a storage controller attempts to collapse the medium graph, thus reducing the number of mediums in which the storage controller must look to find a given block. One technique for collapsing the medium graph involves promoting individual mappings from a lower-level medium to a higher-level medium. Another technique for collapsing the medium graph involves pushing medium range pointers higher up in the medium mapping table to reduce the number of mediums that must be searched.

Claims

1. A method for use in a storage system, the method comprising:

receiving a request to restore a logical volume that represents logical storage on the storage system; and

responsive to receiving the request to restore the logical volume;

determining that the logical volume previously mapped to a logical data representation that currently maps to data stored on the storage system; and

in response to determining that the logical volume previously mapped to the logical data representation that currently maps to data stored on the storage system, restoring the connection between the logical volume and the data stored on the storage system by logically remapping the logical volume to the logical data representation.

2. The method of claim 1 wherein logically remapping the logical volume to the logical data representation includes:

creating a new entry in a volume to logical data representation mapping table, wherein the new entry includes an indication that the logical volume is mapped to the logical data representation.

3. The method of claim 1 wherein logically remapping the logical volume to the logical data representation includes:

creating a second logical data representation of the logical volume;

storing an indication that the second logical data representation is mapped to the logical data representation; and

creating a new entry in a volume to representation mapping table, wherein the new entry includes a second indication that the logical volume is mapped to the second logical data representation.

4. The method of claim 1 further comprising indicating within a volume to logical data representation mapping table that the logical volume was previously mapped to the data logical representation;

wherein the logical data representation refers to a point-in-time of the data stored on the storage system.

5. The method of claim 1 further comprising:

receiving a request to delete the logical volume;

responsive to receiving the request to delete the logical volume;

determining the logical volume is mapped to a particular logical data representation of the logical volume;

indicating that the logical volume was previously mapped to the particular logical data representation of the logical volume; and

removing any indication that the logical volume is valid.

6. The method of claim 5 further comprising maintaining a volume to logical data representation mapping table to track relationships between volumes and logical data representations of volumes;

wherein removing any indication that the logical volume is valid comprises deleting, within the volume to logical data representation mapping table, an entry corresponding to the logical volume.

7. The method of claim 5 further comprising responsive to receiving the request to delete the logical volume, delaying deletion of the particular logical data representation for a first period of time.

8. A computer system comprising:

one or more storage devices; and

a storage controller coupled to the one or more storage devices, wherein the storage controller is configured to;

receive a request to restore a logical volume that represents logical storage on the storage system; and

responsive to receiving the request to restore the logical volume;

determine that the logical volume previously mapped to a logical data representation that currently maps to data stored on the storage system; and

in response to determining that the logical volume previously mapped to the logical data representation that currently maps to data stored on the storage system, restore the connection between the logical volume and the data stored on the storage system by logically remapping the logical volume to the logical data representation.

9. The computer system of claim 8 wherein logically remapping the logical volume to the logical data representation includes:

creating a new entry in a volume to logical data representation mapping table, wherein the new entry includes an indication that the logical volume is mapped to the logical data representation.

10. The computer system of claim 8 wherein logically remapping the logical volume to the logical data representation includes:

creating a second logical data representation of the logical volume;

storing an indication that the second logical data representation is mapped to the logical data representation; and

creating a new entry in a volume to representation mapping table, wherein the new entry includes a second indication that the logical volume is mapped to the second logical data representation.

11. The computer system of claim 8 wherein the storage controller is further configured to indicate within a volume to logical data representation mapping table that the logical volume was previously mapped to the data logical representation;

wherein the logical data representation refers to a point-in-time of the data stored on the storage system.

12. The computer system of claim 8, wherein the storage controller is further configured to:

receive a request to delete the logical volume;

responsive to receiving the request to delete the logical volume;

determine the logical volume is mapped to a particular logical data representation of the logical volume;

indicate that the logical volume was previously mapped to the particular logical data representation of the logical volume; and

remove any indication that the logical volume is valid.

13. The computer system of claim 12 wherein the storage controller is further configured to:

maintain a volume to logical data representation mapping table to track relationships between volumes and logical data representations of volumes;

wherein removing any indication that the logical volume is valid comprises deleting, within the volume to logical data representation mapping table, an entry corresponding to the logical volume.

14. The computer system of claim 12 wherein the storage controller is further configured to:

responsive to receiving the request to delete the logical volume, delay deletion of the particular logical data representation for a first period of time.

15. A non-transitory computer readable storage medium storing program instructions, wherein the program instructions are executable by a processor to:

receive a request to restore a logical volume; and

responsive to receiving the request to restore the logical volume that represents logical storage on the storage system;

determine that the logical volume previously mapped to a logical data representation that currently maps to data stored on the storage system; and

in response to determining that the logical volume previously mapped to the logical data representation that currently maps to data stored on the storage system, restore the connection between the logical volume and the data stored on the storage system by logically remapping the logical volume to the logical data representation.

16. The computer readable storage medium of claim 15 includes:

creating a new entry in a volume to logical data representation mapping table, wherein the new entry includes an indication that the logical volume is mapped to the logical data representation.

17. The computer readable storage medium of claim 15 wherein logically remapping the logical volume to the logical data representation includes:

creating a second logical data representation of the logical volume;

storing an indication that the second logical data representation is mapped to the logical data representation; and

creating a new entry in a volume to representation mapping table, wherein the new entry includes a second indication that the logical volume is mapped to the second logical data representation.

18. The computer readable storage medium of claim 15 wherein the program instructions are executable by a processor to indicate within a volume to logical data representation mapping table that the logical volume was previously mapped to the logical data representation;

wherein the logical data representation refers to a point-in-time of the data stored on the storage system.

19. The computer readable storage medium of claim 15,

wherein the program instructions are executable by a processor to:

receive a request to delete the logical volume;

responsive to receiving the request to delete the logical volume;

determine the logical volume is mapped to a particular logical data representation of the logical volume;

indicate that the logical volume was previously mapped to the particular logical data representation of the logical volume; and

remove any indication that the logical volume is valid.

20. The computer readable storage medium of claim 19 wherein the program instructions are executable by a processor to:

maintain a volume to logical data representation mapping table to track relationships between volumes and logical data representations of volumes;

wherein removing any indication that the logical volume is valid comprises deleting, within the volume to logical data representation mapping table, an entry corresponding to the logical volume.