Patent Application

App. No. 17/303,506

Abstract

Claims (31)

1 . A non-transitory tangible computer readable storage medium having stored thereon a computer program for creating recovery point objectives in persistent memory, the computer program including a set of instructions which, when executed by a computer, cause the computer to perform a method comprising the steps of:

maintaining a virtual memory mapping table data structure, the virtual memory mapping table data structure including entries correlating virtual addresses of tracks of a customer-defined storage volume with physical addresses of memory regions of persistent memory, each entry further including a snapshot instance identifier identifying a recovery point objective of data stored at the respective memory region of persistent memory;

receiving a first write operation to a first track of the customer-defined storage volume;

reading a first entry associated with a first virtual address of the first track from the virtual memory mapping table, to determine a first memory region of the persistent memory where the first track should be stored in persistent memory, and to determine a respective a first snapshot instance identifier;

comparing the first snapshot instance identifier with a current snapshot instance identifier associated with the customer-defined storage volume;

when the first snapshot instance identifier is the same as the current snapshot instance identifier associated with the customer-defined storage volume, writing the first track to the first memory region of persistent memory; and

when the first snapshot instance identifier is not the same as the current snapshot instance identifier associated with the customer-defined storage volume, copying first data from the first memory region of persistent memory to a snapshot repository before writing the first track to the first memory region of persistent memory.

2 . The non-transitory tangible computer readable storage medium of claim 1 , wherein the snapshot repository is implemented using storage other than the persistent memory.

3 . The non-transitory tangible computer readable storage medium of claim 1 , further comprising adding an entry to the virtual memory mapping table identifying the first data, a physical address where the first data is stored in the snapshot repository, and the first snapshot instance identifier.

4 . The non-transitory tangible computer readable storage medium of claim 1 , wherein the persistent memory is implemented using Storage Class Memory (SCM).

5 . The non-transitory tangible computer readable storage medium of claim 4 , wherein the SCM is configured such that data stored in the SCM is not lost during a power loss event.

6 . The non-transitory tangible computer readable storage medium of claim 1 , further comprising adding a second entry for the first data identifying a location of the first data in the snapshot repository.

7 . A method of creating a recovery point objective in persistent memory, comprising:

storing a plurality of tracks of data of a customer-defined storage volume associated with a first snapshot instance identifier in memory regions of persistent memory;

assigning a second snapshot instance identifier to the customer-defined storage volume; and

implementing a write operation on a first of the memory regions of the persistent memory, the write operation causing data stored in the first memory region to be copied to a snapshot repository, and then new data associated with the write operation to be written to the first memory region.

8 . The method of claim 7 , wherein the second snapshot instance identifier is associated with the first memory region when the write operation is implemented on the first memory region.

9 . The method of claim 7 , further comprising maintaining a virtual memory mapping table containing entries correlating the plurality of tracks of data of the customer-defined storage volume with the addresses of the memory regions of persistent memory.

10 . The method of claim 9 , wherein each entry contains a snapshot instance identifier identifying a snapshot instance identifier of the customer-defined storage volume at the time the data contained at a respective memory region was written to persistent memory.

11 . The method of claim 9 , wherein the virtual memory mapping table further containing entries specifying locations of tracks in the snapshot repository.

12 . The method of claim 7 , further comprising:

creating a snapshot filesystem associated with the first snapshot instance identifier by retrieving a first subset of tracks of data of the customer-defined storage volume having the first snapshot identifier from memory regions of the persistent memory, and retrieving a second subset of tracks of data of the customer-defined storage volume having the first snapshot identifier from the snapshot repository.

13 . The method of claim 7 , wherein the persistent memory is implemented using Storage Class Memory (SCM).

14 . The method of claim 13 , wherein the SCM is configured such that data stored in the SCM is not lost during a power loss event.

15 . A virtual memory mapping table data structure, comprising:

a plurality of entries correlating virtual addresses of tracks of a customer-defined storage volume with physical addresses of memory regions of persistent memory, each entry further including a snapshot instance identifier identifying a recovery point objective of data stored at the respective memory region of persistent memory.

16 . The virtual memory mapping table data structure of claim 15 , wherein at least some of the plurality of entries contain different snapshot instance identifiers.

17 . The virtual memory mapping table data structure of claim 15 , wherein the virtual memory mapping table further comprises a first snapshot page containing entries identifying memory regions of a snapshot repository, each entry being associated with a particular track of data of the customer-defined storage volume that has a first snapshot instance identifier.

18 . The virtual memory mapping table data structure of claim 17 , wherein the snapshot repository is implemented using storage other than the persistent memory.

19 . The virtual memory mapping table data structure of claim 15 , wherein the persistent memory is implemented using Storage Class Memory (SCM).

20 . The virtual memory mapping table data structure of claim 19 , wherein the SCM is configured such that data stored in the SCM is not lost during a power loss event.

Assignments (8)