Restoring snapshots in a storage system

• US 10,235,093 B1
• Filed: 04/11/2017
• Issued: 03/19/2019
• 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): Bragdon, Reginald G
• Assistant Examiner(s): Namazi, Mehdi
• Application Number:
  US15/484,243
• Time in Patent Office: 707 Days
• 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 creating and managing snapshots. Mediums are recorded and maintained, all of which are read-only except for the most recent mediums in use by a volume. Multiple volumes may be maintained, including a first volume which points to a first medium. When a snapshot of the first volume is taken, a second medium is created that points to the first medium. The first volume is also updated to point to the second medium. The first medium becomes the underlying medium of the second medium, and lookups are performed initially on the second medium and then on the first medium if the data is not located in the second medium.

Claims

1. A method comprising:

receiving, by the storage controller, a request to restore a previously taken snapshot;

identifying, by the storage controller, a first logical grouping of data corresponding to the previously taken snapshot;

creating, by the storage controller, a second logical grouping of data;

creating, by the storage controller, a new entry for the second logical grouping of data in a medium mapping table;

recording in the medium mapping table, by the storage controller, the first logical grouping of data as underlying the second logical grouping of data;

associating, by the storage controller, a volume with the first logical grouping of data; and

returning, by the storage controller, an identification of the volume to a user device responsible for generating the snapshot request.

2. The method of claim 1 wherein associating a volume with the first logical grouping of data includes updating a volume to medium mapping table so that the volume directly points to the first logical grouping of data.

3. The method of claim 1 further comprising creating, by the storage controller, a new volume, wherein associating a volume with the first logical grouping of data includes associating the new volume with the first logical grouping of data.

4. The method of claim 1 further comprising identifying, by the storage controller, an existing volume, wherein associating a volume with the first logical grouping of data includes associating the existing volume with the first logical grouping of data.

5. The method of claim 1 wherein associating a volume with the first logical grouping of data includes updating a volume to medium mapping table so that the volume directly points to the second logical grouping of data.

6. The method of claim 1 wherein the volume is an existing volume.

7. An apparatus comprising a storage controller and a computer readable storage medium, wherein the computer readable storage medium includes program instructions that when executed by the storage controller cause the apparatus to carry out operations comprising:

receiving, by the storage controller, a request to restore a previously taken snapshot;

identifying, by the storage controller, a first logical grouping of data corresponding to the previously taken snapshot;

creating, by the storage controller, a second logical grouping of data;

creating, by the storage controller, a new entry for the second logical grouping of data in a medium mapping table;

recording in the medium mapping table, by the storage controller, the first logical grouping of data as underlying the second logical grouping of data;

associating, by the storage controller, a volume with the first logical grouping of data; and

returning, by the storage controller, an identification of the volume to a user device responsible for generating the snapshot request.

8. The apparatus of claim 7 wherein associating a volume with the first logical grouping of data includes updating a volume to medium mapping table so that the volume directly points to the first logical grouping of data.

9. The apparatus of claim 7 wherein the computer readable storage medium includes program instructions that when executed by the storage controller cause the apparatus to execute further instructions comprising creating, by the storage controller, a new volume;

wherein associating a volume with the first logical grouping of data includes associating the new volume with the first logical grouping of data.

10. The apparatus of claim 7 wherein the computer readable storage medium includes program instructions that when executed by the storage controller cause the apparatus to execute further instructions comprising identifying, by the storage controller, an existing volume;

wherein associating a volume with the first logical grouping of data includes associating the existing volume with the first logical grouping of data.

11. The apparatus of claim 7 wherein associating a volume with the first logical grouping of data includes updating a volume to medium mapping table so that the volume directly points to the second logical grouping of data.

12. The apparatus of claim 7 wherein the volume is an existing volume.

13. A computer readable storage medium, the computer readable storage medium including program instructions that when executed by a storage controller cause the storage controller to carry out instructions comprising:

receiving, by the storage controller, a request to restore a previously taken snapshot;

identifying, by the storage controller, a first logical grouping of data corresponding to the previously taken snapshot;

creating, by the storage controller, a second logical grouping of data;

creating, by the storage controller, a new entry for the second logical grouping of data in a medium mapping table;

recording in the medium mapping table, by the storage controller, the first logical grouping of data as underlying the second logical grouping of data;

associating, by the storage controller, a volume with the first logical grouping of data; and

returning, by the storage controller, an identification of the volume to a user device responsible for generating the snapshot request.

14. The computer readable storage medium of claim 13 wherein associating a volume with the first logical grouping of data includes updating a volume to medium mapping table so that the volume directly points to the first logical grouping of data.

15. The computer readable storage medium of claim 13 further comprising computer program instructions that when executed by a computer cause the computer to carry out the steps of creating, by the storage controller, a new volume;

wherein associating a volume with the first logical grouping of data includes associating the new volume with the first logical grouping of data.

16. The computer readable storage medium of claim 13 further comprising computer program instructions that when executed by the storage controller cause the storage controller to execute the instructions of identifying, by the storage controller, an existing volume;

wherein associating a volume with the first logical grouping of data includes associating the existing volume with the first logical grouping of data.

17. The computer readable storage medium of claim 13 wherein associating a volume with the first logical grouping of data includes updating a volume to medium mapping table so that the volume directly points to the second logical grouping of data.