Resizing snapshot mount points

• US 9,047,169 B1
• Filed: 03/30/2012
• Issued: 06/02/2015
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Haase, David, de Forest, Miles A., Haynes, Michael D., Seela, Nagapraveen V., Suldhal, Dayanand, McGrath, Paul T., Goudreau, Robert F. Jr.
• Primary Examiner(s): OBISESAN, AUGUSTINE KUNLE
• Application Number:
  US13/435,519
• Time in Patent Office: 1,159 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 12/00 Accessing, addressing or allocating within memory systems or architectures digital input from, or digital output to record carriers, e.g. to disk storage units, G06F3/06
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0614 Improving the reliability of storage systems
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: Y10S 16/04 Mirror mount

Abstract

A method is used for managing snapshot mount points in storage systems. A request to resize a snapshot mount point is received and a file object associated with the snapshot mount point is retrieved. The file object is analyzed to determine a file attached to the snapshot mount point and a file ID is determined for an underlying file associated with the determined file. The file associated with the file ID is resized.

Claims

1. A method for use in resizing snapshot mount points in storage systems, the method comprising:

receiving a request to resize a snapshot mount point, wherein the snapshot mount point is selected from a set of snapshot mount points, wherein the snapshot mount point is a logical object accessible for using a replica of a logical volume and provides a set of interfaces for resizing the replica of the logical volume, wherein the replica of the logical volume represents a state of the logical volume at a particular prior point in time;

retrieving a file object associated with the snapshot mount point;

analyzing the file object to determine a file attached to the snapshot mount point;

determining a file ID for an underlying file associated with the determined file; and

resizing the file associated with the file ID via the snapshot mount point.

2. The method of claim 1, wherein the resize operation includes expanding the snapshot mount point.

3. The method of claim 1, wherein the resize operation includes shrinking the snapshot mount point.

4. The method of claim 3, further including returning freed storage space resulting for the shrink operation to a storage pool associated with the snapshot mount point.

5. The method of claim 2, further including reporting the original snapshot mount point size before the resize operation completes successfully and reporting the new snapshot mount point size after the resize operation completes successfully.

6. The method of claim 3, further including reporting the new snapshot mount point size when the resize operation begins and fail any read or write operations to storage space beyond the new snapshot mount point'"'"'s last logical block address.

7. The method of claim 1, further including notifying a host that the snapshot mount point has been resized.

8. The method of claim 7, further including causing the host to perform a bus rescan.

9. The method of claim 1, wherein the snapshot mount point is associated with a point in time replica of a base LUN or snapshot LUN.

10. The method of claim 1, wherein the snapshot mount point is associated with a logical object selected from the group consisting of:

thin LUN, fully provisioned LUN, partially provisioned LUN, mapped replica of a thin LUN, mapped replica of a fully provisioned LUN, mapped replica of a partially provisioned LUN, snapshots of snaps, snapshot LUNs, and snapshot consistency groups.

11. A system for use in resizing snapshot mount points in storage systems, the system comprising a processor configured to:

receive to a request to resize a snapshot mount point, wherein the snapshot mount point is selected from a set of snapshot mount points, wherein the snapshot mount point is a logical object accessible for using a replica of a logical volume and provides a set of interfaces for resizing the replica of the logical volume, wherein the replica of the logical volume represents a state of the logical volume at a particular prior point in time;

retrieve a file object associated with the snapshot mount point;

analyze the file object to determine a file attached to the snapshot mount point;

determine a file ID for an underlying file associated with the determined file; and

resize the file associated with the file ID via the snapshot mount point.

12. The system of claim 11, wherein the resize operation includes expanding the snapshot mount point.

13. The system of claim 11, wherein the resize operation includes shrinking the snapshot mount point.

14. The system of claim 13, wherein the processor is further configured to return freed storage space resulting for the shrink operation to a storage pool associated with the snapshot mount point.

15. The system of claim 12, wherein the processor is further configured to report the original snapshot mount point size before the resize operation completes successfully and reporting the new snapshot mount point size after the resize operation completes successfully.

16. The system of claim 13, wherein the processor is further configured to report the new snapshot mount point size when the resize operation begins and fail any read or write operations to storage space beyond the new snapshot mount point'"'"'s last logical block address.

17. The system of claim 11, wherein the processor is further configured to notify a host that the snapshot mount point has been resized.

18. The system of claim 17, wherein the processor is further configured to cause the host to perform a bus rescan.

19. The system of claim 11, wherein the snapshot mount point is associated with a point in time replica of a base LUN or snapshot LUN.

20. The system of claim 11, wherein the snapshot mount point is associated with a logical object selected from the group consisting of:

thin LUN, fully provisioned LUN, partially provisioned LUN, mapped replica of a thin LUN, mapped replica of a fully provisioned LUN, mapped replica of a partially provisioned LUN, snapshots of snaps, snapshot LUNs, and snapshot consistency groups.