Data replication within a flash storage array

• US 10,656,864 B2
• Filed: 03/20/2014
• Issued: 05/19/2020
• Est. Priority Date: 03/20/2014
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Pure Storage, Inc.
• Inventors: Bernat, Andrew R., Ramanarayanan, Ganesh, Sharpe, Malcolm, Hodgson, Steve, Miller, Ethan, Driscoll, Alan, Golden, Christopher, Colgrove, John
• Primary Examiner(s): Lo, Ann J
• Assistant Examiner(s): Wei, Jane
• Application Number:
  US14/220,908
• Publication Number:
  US 20150268864A1
• Time in Patent Office: 2,252 Days
• Field of Search: None
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• 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 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/065 Replication mechanisms
• 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 3/0683 Plurality of storage devices

Abstract

A system and method for performing replication using mediums. A snapshot ‘S’ is selected for replication, and the anchor medium ‘M’ of S is identified. The replica storage array ‘R’ to which M is being replicated determines a list of medium extents which are available. R sends this list to an original storage array ‘O’ and O generates a list of medium extents which need to be sent to R. Only those medium extents corresponding to M which R does not already have will be sent from O to R. Also, R can obtain medium extents from other source storage arrays during the replication process.

Claims

1. A system comprising:

a first storage array configured to;

responsive to a request to replicate a snapshot of a volume from a first storage array to a second storage array, identify a group of data corresponding to the snapshot;

during replication of the group of data from the first storage array to the second storage array, determine that a non-replicated region of the group is a duplicate of a replicated region of the group; and

in response to the first storage array determining that the non-replicated region is a duplicate of the replicated region stored on the second storage array, send, from the first storage array to the second storage array, a reference to the non-replicated region instead of sending data for the non-replicated region, the reference including an address where the non-replicated region is stored on the first storage array;

maintain a second list of regions which are already stored on the second storage array and which map to a region of the group of data; and

a second storage array configured to, responsive to detecting the request to replicate the snapshot of the volume from the first storage array to the second storage array;

identify a plurality of regions stored on the second storage array which correspond to groups of data that originated on the first storage array; and

send a first list of the plurality of regions to the first storage array;

wherein the first storage array is remote from the second storage array.

2. The system as recited in claim 1, wherein the first storage array is further configured to:

receive the first list from the second storage array;

for each region of the first list;

determine if the region maps to any region of the group of data; and

store the region in the second list responsive to determining the region maps to a given region of the group of data.

3. The system as recited in claim 2, wherein the first storage array is further configured to add a first region to the second list responsive to sending the first region to the second storage array and receiving an acknowledgement from the second storage array that the second storage array has received the first region.

4. The system as recited in claim 3, wherein the first storage array is further configured to add a second region to the second list responsive to receiving an acknowledgement from the second storage array that the second storage array has received the second region from a third storage array.

5. The system as recited in claim 3, wherein the first storage array is further configured to generate a third list of duplicate regions of the group of data that are mapped to each other, wherein the third list is generated by traversing a medium mapping table for each region of the group of data.

6. The system as recited in claim 5, wherein the first storage array is further configured to:

maintain a fourth list of mappings, wherein each entry of the fourth list maps a physical location to a region of the group of data that has already been sent to the second storage array; and

prior to sending data corresponding to a given physical location to the second storage array, check the fourth list for a match to the given physical location.

7. A method comprising:

responsive to a request to replicate a snapshot of a volume from a first storage array to a second storage array;

identifying a group of data corresponding to the snapshot;

during replication of the group of data from the first storage array to the second storage array, determining that a non-replicated region of the group is a duplicate of a replicated region of the group;

in response to the first storage array determining that the non-replicated region is a duplicate of the replicated region stored on the second storage array, sending, from the first storage array to the second storage array, a reference to the non-replicated region instead of sending data for the non-replicated region, the reference including an address where the non-replicated region is stored on the first storage array;

identifying a plurality of regions stored on the second storage array which correspond to groups of data that originated on the first storage array;

sending a first list of the plurality of regions from the second storage array to the first storage array;

maintaining a second list of regions which are already stored on the second storage array and which map to a region of the group of data, wherein the second list is maintained on the first storage array; and

wherein the first storage array is remote from the second storage array.

8. The method as recited in claim 7, further comprising:

receiving the first list from the second storage array;

for each region of the first list;

determining if the region maps to any region of the group of data; and

storing the region in the second list responsive to determining the region maps to a given region of the group of data.

9. The method as recited in claim 8, further comprising adding a first region to the second list responsive to sending the first region to the second storage array and receiving an acknowledgement from the second storage array that the second storage array has received the first region.

10. The method as recited in claim 9, further comprising adding a second region to the second list responsive to receiving an acknowledgement from the second storage array that the second storage array has received the second region from a third storage array.

11. The method as recited in claim 9, further comprising generating a third list of duplicate regions of the group of data that are mapped to each other, wherein the third list is generated by traversing a medium mapping table for each region of the group of data.

12. The method as recited in claim 11, further comprising:

maintaining a fourth list of mappings, wherein each entry of the fourth list maps a physical location to a region of the group of data that has already been sent to the second storage array; and

prior to sending data corresponding to a given physical location to the second storage array, checking the fourth list for a match to the given physical location.

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

responsive to a request to replicate a snapshot of a volume from a first storage array to a second storage array;

identify a group of data corresponding to the snapshot;

during replication of the group of data from the first storage array to the second storage array, determine that a non-replicated region of the group is a duplicate of a replicated region of the group;

in response to the first storage array determining that the non-replicated region is a duplicate of the replicated region stored on the second storage array, send, from the first storage array to the second storage array, a reference to the non-replicated region instead of sending data for the non-replicated region, the reference including an address where the non-replicated region is stored on the first storage array;

identify a plurality of regions stored on the second storage array which correspond to groups of data that originated on the first storage array;

send a first list of the plurality of regions from the second storage array to the first storage array;

maintain a second list of regions which are already stored on the second storage array and which map to a region of the group of data, wherein the second list is maintained on the first storage array; and

wherein the first storage array is remote from the second storage array.

14. The computer readable storage medium as recited in claim 13, wherein the program instructions are further executable by a processor to:

receive the first list from the second storage array;

for each region of the first list;

determine if the region maps to any region of the group of data; and

store the region in the second list responsive to determining the region maps to a given region of the group of data.

15. The computer readable storage medium as recited in claim 14, wherein the program instructions are further executable by a processor to add a first region to the second list responsive to sending the first region to the second storage array and receiving an acknowledgement from the second storage array that the second storage array has received the first region.

16. The computer readable storage medium as recited in claim 15, wherein the program instructions are further executable by a processor to add a second region to the second list responsive to receiving an acknowledgement from the second storage array that the second storage array has received the second region from a third storage array.

17. The computer readable storage medium as recited in claim 15, wherein the program instructions are further executable by a processor to generate a third list of duplicate regions of the group of data that are mapped to each other, wherein the third list is generated by traversing a medium mapping table for each region of the group of data.