Method and system for implementing high availability storage on thinly provisioned arrays
View Patent ↗A method for storage allocation and reclamation in a storage device. The method includes executing a distributed computer system having a plurality of file systems accessing storage on a shared storage device, creating a physical storage allocation state map that indicates whether a plurality of data blocks comprising a range of data is allocated or unallocated, and consulting a free extent state map to identify free data blocks of the shared storage device. An allocation operation is performed causing the shared storage device to allocate storage a requested range of allocation. The physical storage allocation state map is updated in accordance with the requested range of allocation. Upon a subsequent reclamation process, the physical storage allocation state map is accessed to identify free previously allocated data blocks. Reclamation processing a subsequent performed on the identified free previously allocated data blocks.
1. A method for storage allocation and reclamation in a storage device, comprising:
creating a physical storage allocation state map that indicates whether a plurality of data blocks comprising a range of data is allocated or unallocated in a shared storage device, wherein a default state of the physical storage allocation state map indicates no allocated storage for the plurality of data blocks;
consulting a free extent state map to identify free data blocks of the shared storage device, wherein the free extent state map is separate from the physical storage allocation state map;
performing an allocation operation causing the shared storage device to allocate storage over a requested range of allocation, wherein the allocation operation preferentially allocates storage to a first plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map;
updating the physical storage allocation state map in accordance with the requested range of allocation;
upon a subsequent reclamation process, accessing the physical storage allocation state map to identify a second plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map; and
performing reclamation processing on the identified second plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map.
2. The method of claim 1 , wherein the free extent state map is consulted to identify and allocate free data blocks of the shared storage device, and wherein the physical storage allocation state map is consulted to determine whether physical storage of the shared storage device is known to have been previously allocated.
3. The method of claim 1 , wherein the physical storage allocation state map comprises a map that tracks a storage condition of a plurality of chunks of data having a predetermined size.
4. The method of claim 1 , wherein the physical storage allocation state map comprises a bitmap, and wherein bits of the bitmap track a storage condition of a plurality of chunks of data having a predetermined size.
5. The method of claim 1 , wherein the physical storage allocation state map is accessed to preferentially free blocks of the shared storage device that are indicated as previously allocated.
6. The method of claim 1 , wherein the shared storage device comprises a disk array.
7. The method of claim 1 , wherein the shared storage device is part of a cluster of a distributed computer system.
8. A non-transitory computer readable storage medium having stored thereon computer executable instructions that, if executed by a computer system, cause the computer system to perform a method comprising:
creating a physical storage allocation state map that indicates whether a plurality of data blocks comprising a range of data is allocated or unallocated in a shared storage device, wherein a default state of the physical storage allocation state map indicates no allocated storage for the plurality of data blocks;
consulting a free extent state map to identify free data blocks of the shared storage device, wherein the free extent state map is separate from the physical storage allocation state map;
performing an allocation operation causing the shared storage device to allocate storage over a requested range of allocation, wherein the allocation operation preferentially allocates storage to a first plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map;
updating the physical storage allocation state map in accordance with the requested range of allocation;
upon a subsequent reclamation process, accessing the physical storage allocation state map to identify a second plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map; and
performing reclamation processing on the identified second plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map.
9. The non-transitory computer readable storage medium of claim 8 , wherein the free extent state map is consulted to identify and allocate free data blocks of the shared storage device, and wherein the physical storage allocation state map is consulted to determine whether physical storage of the shared storage device is known to have been previously allocated.
10. The non-transitory computer readable storage medium of claim 8 , wherein the physical storage allocation state map comprises a map that tracks a storage condition of a plurality of chunks of data having a predetermined size.
11. The non-transitory computer readable storage medium of claim 8 , wherein the physical storage allocation state map comprises a bitmap, and wherein bits of the bitmap track a storage condition of a plurality of chunks of data having a predetermined size.
12. The non-transitory computer readable storage medium of claim 8 , wherein the physical storage allocation state map is accessed to preferentially free blocks of the shared storage device that are indicated as previously allocated.
13. The non-transitory computer readable storage medium of claim 8 , wherein the shared storage device comprises a disk array.
14. The non-transitory computer readable storage medium of claim 8 , wherein the shared storage device is part of a cluster of a distributed computer system.
15. A computer system having a microprocessor coupled to a computer readable memory, the memory having computer readable code therein which when executed by the computer system causes the computer system to implement a method comprising:
creating a physical storage allocation state map that indicates whether a plurality of data blocks comprising a range of data is allocated or unallocated in a shared storage device, wherein a default state of the physical storage allocation state map indicates no allocated storage for the plurality of data blocks;
consulting a free extent state map to identify free data blocks of the shared storage device, wherein the free extent state map is separate from the physical storage allocation state map;
performing an allocation operation causing the shared storage device to allocate storage over a requested range of allocation, wherein the allocation operation preferentially allocates storage to a first plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map;
updating the physical storage allocation state map in accordance with the requested range of allocation;
upon a subsequent reclamation process, accessing the physical storage allocation state map to identify a second plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map; and
performing reclamation processing on the identified second plurality of data blocks that are marked as free blocks in the free extent state map and as having been allocated in the physical storage allocation state map.
16. The computer system of claim 15 , wherein the free extent state map is consulted to identify and allocate free data blocks of the shared storage device, and wherein the physical storage allocation state map is consulted to determine whether physical storage of the shared storage device is known to have been previously allocated.
17. The computer system of claim 15 , wherein the physical storage allocation state map comprises a map that tracks a storage condition of a plurality of chunks of data having a predetermined size.
18. The computer system of claim 15 , wherein the physical storage allocation state map comprises a bitmap, and wherein bits of the bitmap track a storage condition of a plurality of chunks of data having a predetermined size.
19. The computer system of claim 15 , wherein the physical storage allocation state map is accessed to preferentially free blocks of the shared storage device that are indicated as previously allocated.
20. The computer system of claim 8 , wherein the shared storage device comprises a disk array, and wherein the shared storage device is part of a cluster of a distributed computer system.