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; and
a circuit configured to indicate when a retention period is reached, wherein:
each storage device is operable to store one or more data blocks,
each of the data blocks is associated with a deletion state,
each of the data blocks that is not at a highest deletion state, when the retention period is reached, is incremented to a next higher deletion state,
a data block is reset to a lowest deletion state if the data block is accessed,
each storage device of the plurality of storage devices is assigned to one of an upper tier and a lower tier, and
the system comprises a processor configured to read the deletion state associated with a particular data block in a storage device assigned to the upper tier and demote the particular data block to a storage device assigned to the lower tier if the particular data block is at the highest deletion state.
2. The system of claim 1 , wherein the system comprises a processor configured to read the deletion state associated with a particular data block and delete the particular data block if the particular data block is at the highest deletion state.
3. The system of claim 1 , wherein a particular data block is reset to a lowest deletion state if the particular data block is read.
4. The system of claim 1 , wherein each of the data blocks is associated with a demotion state.
5. The system of claim 4 , wherein the circuit is configured to indicate when a demotion period is reached.
6. The system of claim 5 , wherein:
each of the data blocks that is not at a highest demotion state, when the demotion period is reached, is incremented to a next higher demotion state, and
if a write access is made to a particular data block, the particular data block is reset to a lowest demotion state.
7. The system of claim 6 , wherein the each of the data blocks at the highest demotion state is demoted to a storage device assigned to the lower tier.
8. The system of claim 1 , wherein the each of the data blocks is a 4 kilobyte data block.
9. The system of claim 1 , wherein the each of the data blocks at the highest deletion state is deleted from a read cache.
10. A method comprising:
assigning a deletion state to each of a plurality of data blocks;
resetting a data block of the plurality of data blocks to a lowest deletion state if the data block is accessed;
measuring a retention period;
after the retention period, incrementing each of the plurality of data blocks that are not already at a highest deletion state, to a next higher deletion state;
storing each of the plurality of data blocks in a storage device of a plurality of storage devices;
assigning each of the plurality of storage devices to one of a plurality of tiers; and
demoting a particular data block to a storage device assigned to a lower tier if the particular data block is at the highest deletion state.
11. The method of claim 10 , wherein the method comprises deleting each data block at the highest deletion state.
12. The method of claim 10 , wherein the method comprises resetting a particular data block to a lowest deletion state if the particular data block is read.
13. The method of claim 10 , wherein the method comprises associating each of the plurality of data blocks with a demotion state.
14. The method of claim 13 , wherein the method comprises measuring to a demotion period.
15. The method of claim 14 , wherein the method comprises:
after the demotion period, incrementing each of the data blocks that is not at a highest demotion state, to a next higher demotion state; and
if a write access is made to a particular data block, resetting the particular data block to a lowest demotion state.
16. The method of claim 15 , wherein the method comprises demoting each of the data blocks at the highest demotion state to a storage device assigned to a lower tier.
17. The method of claim 10 , wherein the each of the data blocks is a 4 kilobyte data block.
18. The method of claim 10 , wherein the method comprises, if a particular data block is at the highest deletion state, deleting the particular data block from a read cache.
19. A system comprising:
a plurality of storage devices; and
a circuit configured to indicate when a retention period is reached, wherein:
each storage device is operable to store one or more data blocks,
each of the data blocks is associated with a deletion state,
each of the data blocks that is not at a highest deletion state, when the retention period is reached, is incremented to a next higher deletion state,
a data block is reset to a lowest deletion state if the data block is accessed,
each of the data blocks is associated with a demotion state,
the circuit is configured to indicate when a demotion period is reached,
each of the data blocks that is not at a highest demotion state, when the demotion period is reached, is incremented to a next higher demotion state,
if a write access is made to a particular data block, the particular data block is reset to a lowest demotion state, and
the each of the data blocks at the highest demotion state is demoted to a storage device assigned to the lower tier.
20. The system of claim 19 , wherein the system comprises a processor configured to read the deletion state associated with a particular data block and delete the particular data block if the particular data block is at the highest deletion state.
21. The system of claim 19 , wherein a particular data block is reset to a lowest deletion state if the particular data block is read.
22. The system of claim 19 , wherein the each of the data blocks is a 4 kilobyte data block.
23. The system of claim 19 , wherein the each of the data blocks at the highest deletion state is deleted from a read cache.
24. A method comprising:
assigning a deletion state to each of a plurality of data blocks;
resetting a data block of the plurality of data blocks to a lowest deletion state if the data block is accessed;
measuring a retention period;
after the retention period, incrementing each of the plurality of data blocks that are not already at a highest deletion state, to a next higher deletion state;
associating each of the plurality of data blocks with a demotion state;
measuring to a demotion period;
after the demotion period, incrementing each of the data blocks that is not at a highest demotion state, to a next higher demotion state;
if a write access is made to a particular data block, resetting the particular data block to a lowest demotion state; and
demoting each of the data blocks at the highest demotion state to a storage device assigned to a lower tier.
25. The method of claim 24 , wherein the method comprises deleting each data block at the highest deletion state.
26. The method of claim 24 , wherein the method comprises resetting a particular data block to a lowest deletion state if the particular data block is read.
27. The method of claim 24 , wherein the each of the data blocks is a 4 kilobyte data block.
28. The method of claim 24 , wherein the method comprises, if a particular data block is at the highest deletion state, deleting the particular data block from a read cache.