Tiering data strategy for a distributed storage system
A plurality of computing devices are communicatively coupled to each other via a network, and each of the plurality of computing devices is operably coupled to one or more of a plurality of storage devices. The storage devices may be assigned to one of a plurality of memory tiers, and the data in a storage device may be reassigned to another storage device in a different memory tier.
1. A system comprising:
a plurality of storage devices, wherein:
each storage device of the plurality of storage devices is assigned to one of an upper tier and a lower tier,
each storage device of the plurality of storage devices is operable to store one or more data blocks,
each data block is associated with a deletion state, and
the deletion state associated with a data block is set to a lowest deletion state when the data block is accessed;
a circuit configured to indicate when a retention period is reached; and
a processor configured to:
increment a deletion state of a data block to a next higher deletion state when the retention period is reached and the deletion state of the data block is not already at a highest deletion state, and
demote a data block to a storage device assigned to the lower tier when the retention period is reached, the data block is currently stored in a storage device assigned to the upper tier and the data block is already at a highest deletion state.
2. The system of claim 1 , wherein the processor is configured to delete a data block of the lower tier when the data block is at the highest deletion state.
3. The system of claim 1 , wherein the processor is configured to delete a data block of the lower tier from a read cache when the data block is at the highest deletion state.
4. The system of claim 1 , wherein a particular data block is reset to a lowest deletion state if the particular data block is read.
5. The system of claim 1 , wherein the each of the data blocks is a 4 kilobyte data block.
6. A system comprising:
a plurality of storage devices, wherein:
each storage device of the plurality of storage devices is assigned to one of an upper tier and a lower tier,
each storage device of the plurality of storage devices is operable to store one or more data blocks,
each data block is associated with a demotion state, and
the demotion state associated with a data block is set to a lowest demotion state when the data block is accessed;
a circuit configured to indicate when a retention period is reached; and
a processor configured to:
increment a demotion state of a data block to a next higher demotion state when the retention period is reached and the demotion state of the data block is not already at a highest demotion state, and
demote a data block to a storage device assigned to the lower tier when the retention period is reached, the data block is currently stored in a storage device assigned to the upper tier and the data block is already at a highest demotion state.
7. The system of claim 6 , wherein the processor is configured to delete a data block of the lower tier when the data block is at the highest demotion state.
8. The system of claim 6 , wherein the processor is configured to delete a data block of the lower tier from a write cache when the data block is at the highest demotion state.
9. The system of claim 6 , wherein a particular data block is reset to a lowest demotion state if the particular data block is written.
10. The system of claim 6 , wherein the each of the data blocks is a 4 kilobyte data block.
11. A method comprising:
assigning each storage device of a plurality of storage devices to one of an upper tier and a lower tier;
storing one or more data blocks in each storage device of the plurality of storage devices;
associating each data block with a deletion state;
setting the deletion state associated with a data block to a lowest deletion state when the data block is accessed;
indicating when a retention period is reached;
incrementing a deletion state of a data block to a next higher deletion state when the retention period is reached and the deletion state of the data block is not already at a highest deletion state; and
demoting a data block to a storage device assigned to the lower tier when the retention period is reached, the data block is currently stored in a storage device assigned to the upper tier and the data block is already at a highest deletion state.
12. The method of claim 11 , wherein the method comprises deleting a data block of the lower tier when the data block is at the highest deletion state.
13. The method of claim 11 , wherein the method comprises deleting a data block of the lower tier from a read cache when the data block is at the highest deletion state.
14. The method of claim 11 , wherein the method comprises setting the deletion state associated with a data block to a lowest deletion state when the data block is read.
15. The method of claim 11 , wherein the each of the data blocks is a 4 kilobyte data block.
16. A method comprising:
assigning each storage device of a plurality of storage devices to one of an upper tier and a lower tier;
storing one or more data blocks in each storage device of the plurality of storage devices;
associating each data block with a demotion state;
setting the demotion state associated with a data block to a lowest demotion state when the data block is accessed;
indicating when a retention period is reached;
incrementing a demotion state of a data block to a next higher demotion state when the retention period is reached and the demotion state of the data block is not already at a highest demotion state; and
demoting a data block to a storage device assigned to the lower tier when the retention period is reached, the data block is currently stored in a storage device assigned to the upper tier and the data block is already at a highest demotion state.
17. The method of claim 16 , wherein the method comprises deleting a data block of the lower tier when the data block is at the highest demotion state.
18. The method of claim 16 , wherein the method comprises deleting a data block of the lower tier from a write cache when the data block is at the highest demotion state.
19. The method of claim 16 , wherein the method comprises setting the demotion state associated with a data block to a lowest demotion state when the data block is written.
20. The method of claim 16 , wherein the each of the data blocks is a 4 kilobyte data block.