SYSTEM AND METHOD FOR RETAINING DEDUPLICATION IN A STORAGE OBJECT AFTER A CLONE SPLIT OPERATION

• US 20130054927A1
• Filed: 08/30/2011
• Published: 02/28/2013
• Est. Priority Date: 08/30/2011
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Raj, Bipul, Sharma, Alok
• Granted Patent: US 8,832,035 B2
• Time in Patent Office: Days
• US Class Current: 711/170
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G06F 16/2365 Ensuring data consistency and integrity
• CPC Class Codes: G06F 16/289 Object oriented databases
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• 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 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• 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 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: G06F 9/465 Distributed object oriented systems remote method invocation [RMI] G06F9/548

Abstract

Described herein is a system and method for retaining deduplication of data blocks of a resulting storage object (e.g., a flexible volume) from a split operation of a clone of a base storage object. The clone may comprise data blocks that are shared with at least one data block of the base storage object and at least one data block that is not shared with at least one data block of the base storage object. The data blocks of the clone that are shared with the base storage object may be indicated to receive a write allocation that may comprise assigning a new pointer to a indicated data block. Each data block may comprise a plurality of pointers comprising a virtual address pointer and a physical address pointer. As such, data blocks of the clone comprising the same virtual address pointer may be assigned a single physical address pointer. Thus, a new physical address pointer is assigned or allocated once to a given virtual address pointer of data blocks of a clone.

Claims

1. A system, comprising at least one processor and memory, for managing data on a storage system, the storage system providing data storage for at least one storage object and a clone of the storage object, the system comprising:

the storage system configured for;

receiving a write allocation for a data block of the clone of the storage object, the clone comprises a plurality of data blocks and is based on the storage object, each data block comprises a physical address pointer to a location within a storage aggregate and a virtual address pointer to a location within an address space of the clone of the storage object;

determining if the data block of the clone is shared with at least one data block of the storage object; and

assigning a new pointer to the physical address pointer of the data block of the clone if the data block is shared with at least one data block of the storage object and if a write allocation of another data block of the clone comprising the same virtual address pointer has not been received.

2. The system of claim 1, wherein the clone of the storage object comprises at least one data block shared with at least one data block of the storage object and at least one data block not shared with a data block of the storage object.

3. The system of claim 2, wherein the data block of the clone is shared with at least one data block of the storage object if the physical address pointer of the data block of the clone is the same as a physical address pointer of at least one data block of the storage object.

4. The system of claim 1, the storage operating system is further configured for:

updating, if the new pointer is assigned, a data block map of the clone of the storage object by changing a physical address pointer in the data block map paired with a virtual address pointer corresponding to the virtual address pointer of the data block of the clone with the new pointer.

5. The system of claim 4, the storage operating system is further configured for:

assigning, if the data block of the clone is shared with at least one data block of the storage object and if a write allocation of another data block of the clone comprising the same virtual address pointer has been received, a physical address pointer from the data block map paired with the virtual address pointer corresponding to the virtual address pointer of the data block.

6. The system of claim 1, the storage operating system is further configured for:

receiving a split operation for the clone of the storage object, the split operation indicates all data blocks of the clone that are shared with at least one data block of the storage object, the indicating of the data blocks of the clone results in a write allocation of the indicated data blocks.

7. The system of claim 1, wherein the storage aggregate comprises an address space over a plurality of storage devices.

8. A method for managing data on a storage system, the storage system providing data storage for at least one storage object, and a clone of the storage object the method comprising:

using computer hardware for performing;

receiving a write allocation for a data block of the clone of the storage object, the clone comprises a plurality of data blocks and is based on the storage object, each data block comprises a physical address pointer to a location within a storage aggregate and a virtual address pointer to a location within an address space of the clone of the storage object;

determining if the data block of the clone is shared with at least one data block of the storage object; and

assigning a new pointer to the physical address pointer of the data block of the clone if the data block is shared with at least one data block of the storage object and if a write allocation of another data block of the clone comprising the same virtual address pointer has not been received.

9. The method of claim 8, wherein the clone of the storage object comprises at least one data block shared with at least one data block of the storage object and at least one data block not shared with a data block of the storage object.

10. The method of claim 9, wherein the data block of the clone is shared with at least one data block of the storage object if the physical address pointer of the data block of the clone is the same as a physical address pointer of at least one data block of the storage object.

11. The method of claim 8, the method further comprising:

updating, if the new pointer is assigned, a data block map of the clone of the storage object by changing a physical address pointer in the data block map paired with a virtual address pointer corresponding to the virtual address pointer of the data block of the clone with the new pointer.

12. The method of claim 11, the method further comprising:

assigning, if the data block of the clone is shared with at least one data block of the storage object and if a write allocation of another data block of the clone comprising the same virtual address pointer has been received, a physical address pointer from the data block map paired with the virtual address pointer corresponding to the virtual address pointer of the data block.

13. The method of claim 8, the method further comprising:

receiving a split operation for the clone of the storage object, the split operation indicates all data blocks of the clone that are shared with at least one data block of the storage object, the indicating of the data blocks of the clone results in a write allocation of the indicated data blocks.

14. The method of claim 8, wherein the storage aggregate comprises an address space over a plurality of storage devices.

15. A system, comprising at least one processor and memory, for managing data on a storage system, the storage system providing data storage for at least one deduplicated storage volume comprising a plurality of shared data blocks, each data block comprising a virtual address and a physical address, the system comprising:

the storage system configured for;

creating a clone of the deduplicated storage volume, the clone comprising a plurality of data blocks comprising at least one data block shared with at least one data block of the deduplicated storage volume;

receiving a split operation for the clone, the split operation comprising a write allocation for each data block of the clone that is shared with at least one data block of the deduplicated storage volume; and

retaining deduplication of the data blocks of the clone by assigning a new physical address only once for each virtual address of the data blocks of the clone.

16. The system of claim 15, wherein a first data block and a second data block are shared if the first data block and the second data block each comprise an identical virtual address and an identical physical address.

17. The system of claim 16, wherein the virtual address comprises a pointer to a location within an address space of the clone and the physical address comprises a pointer to a location within a storage aggregate comprising a plurality of storage devices.

18. A non-transitory computer readable medium carrying one or more instructions for managing data on a storage system providing data storage for at least one deduplicated storage volume comprising a plurality of shared data blocks, each data block comprising a virtual address and a physical address, wherein the one or more instructions, when executed by one or more processors, causes the one or more processors to perform the steps of:

creating a clone of the deduplicated storage volume, the clone comprising a plurality of data blocks comprising at least one data block shared with at least one data block of the deduplicated storage volume;

receiving a split operation for the clone, the split operation comprising a write allocation for each data block of the clone that is shared with at least one data block of the deduplicated storage volume; and

retaining deduplication of the data blocks of the clone by assigning a new physical address only once for each virtual address of the data blocks of the clone.

19. The non-transitory computer readable medium of claim 18, wherein a first data block and a second data block are shared if the first data block and the second data block each comprise an identical virtual address and an identical physical address.

20. The non-transitory computer readable medium of claim 19, wherein the virtual address comprises a pointer to a location within an address space of the clone and the physical address comprises a pointer to a location within a storage aggregate comprising a plurality of storage devices.