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; and
each of the one or more data blocks is associated with a state, wherein the state comprises a plurality of deletion states;
a processor configured to read a current state associated with a particular data block in a first storage device of the plurality of storage devices, wherein, according to the current state, the processor is configured to perform one of:
a demotion of the particular data block to a second storage device in the lower tier; and
a deletion of the particular data block from a read cache; and
circuitry configured to count to a retention period, wherein:
if counting to the retention period is finished, the each of the data blocks not at a highest deletion state is incremented to a next higher deletion state, and
if a read access is made to one of the data blocks, the one of the data blocks is reset to a lowest deletion state.
2. The system of claim 1 , wherein the state comprises a plurality of demotion states.
3. The system of claim 2 , comprising circuitry configured to count a demotion period.
4. The system of claim 3 , wherein:
if counting of the demotion period is finished, the each of the data blocks not at a highest demotion state is incremented to a next higher demotion state, and
if a write access is made to the each of the data blocks, the each of the data blocks is reset to a lowest demotion state.
5. The system of claim 4 , wherein the each of the data blocks at the highest demotion state is demoted to the lower tier.
6. The system of claim 1 , wherein the each of the data blocks is a 4 kilobyte data block.
7. The system of claim 1 , wherein the each of the data blocks at the highest deletion state is deleted from the read cache.
8. A method comprising:
performing memory management for each of a plurality of storage devices assigned to one of: an upper tier and a lower tier, wherein:
the each of the plurality of storage device comprises data blocks; and
each of the data blocks has a corresponding state; and
reading, by a processor, the state of the each of the data blocks to, wherein the state comprises a plurality of deletion states;
performing, according to the state, one of:
demoting the each of the data blocks to the lower tier; and
deleting the each of the data blocks from a read cache; and
counting a retention period wherein:
if the count to the retention period is finished, the each of the data blocks not at a highest deletion state is incremented to a next higher deletion state, and
if a read access is made to one of the data blocks, the one of the data blocks is reset to a lowest deletion state.
9. The method of claim 8 , wherein the state comprises a plurality of demotion states.
10. The method of claim 9 , comprising counting a demotion period.
11. The method of claim 10 , wherein:
if counting the demotion period is finished, the each of the data blocks not at a highest demotion state is incremented to a next higher demotion state, and
if a write access is made to the each of the data blocks, the each of the data blocks of memory is reset to a lowest demotion state.
12. The method of claim 11 , wherein the each of the data blocks at the highest demotion state is demoted to the lower tier.
13. The method of claim 8 , wherein the each of the data blocks is a 4 kilobyte block.
14. The method of claim 8 , wherein the each of the data blocks at the highest deletion state is deleted from the read cache.