Persistent storage device management

1. A method comprising:

receiving a request to write data at a virtual location;

writing the data to a physical location on a persistent storage device of a plurality of persistent storage devices, wherein the physical location corresponds to a block within a stripe, the stripe comprising a plurality of blocks, each block being a physical location on each of the plurality of persistent storage devices;

after completing the stripe by writing received data to the physical location of each of the plurality of persistent storage devices, updating a head counter; and

recording a mapping from the virtual location to the physical location on the persistent storage;

wherein the physical location on the persistent storage device corresponds to a next free block in a sequence of blocks on the persistent storage device.

2. The method of claim 1 , wherein the virtual location and the physical location are not correlated.

3. The method of claim 1 , wherein the physical location is determined by the head counter.

4. The method of claim 1 , further comprising:

receiving one or more requests to write further data to corresponding virtual locations;

wherein the data and the further data form a data stream.

5. The method of claim 1 , wherein writing the data to a second location occurs without performing a read from the persistent storage device.

6. The method of claim 1 , further comprising:

calculating a checksum for the data; and

recording the checksum in metadata associated with the persistent storage device.

7. The method of claim 1 , further comprising:

determining that a garbage collection condition is met.

8. The method of claim 7 , wherein the garbage collection condition comprises one or more of:

a number of gaps on the persistent storage device exceeds a predetermined threshold;

an activity level of the persistent storage device falls below a threshold;

a free capacity of the persistent storage device falls below a threshold; or

a time period has passed.

9. The method of claim 7 , further comprising, in response to determining that a garbage collection condition is met:

determining a block at the tail of the sequence of blocks;

writing the data at the block to the head of the sequence of blocks; and

updating the mapping based on the writing.

10. The method of claim 1 , further comprising:

determining that a predetermined number of blocks within the stripe have been written;

calculating parity corresponding to the data written to the predetermined number of blocks within the stripe; and

writing the parity data in one or more blocks within the stripe.

11. The method of claim 10 , further comprising:

retrieving a checksum for the retrieved data;

calculating a checksum for the retrieved data; and

comparing the calculated checksum with the retrieved checksum.

12. The method of claim 1 , further comprising:

determining that a block of a stripe is missing;

reconstructing the data at the missing block from one or more other blocks in the stripe;

writing the data to the head of the sequence of blocks; and

updating the mapping based on the writing.

13. The method of claim 1 , further comprising:

determining that a persistent storage device among the plurality of persistent storage devices is unavailable; and

wherein writing the data to a physical location on a persistent storage device comprises:

writing the data to a physical location on a different one of the persistent storage devices.

14. The method of claim 1 , wherein recording a mapping from the virtual location to the physical location on the persistent storage device comprises:

identifying a mapping from the virtual location to a previous physical location; and

updating the mapping to record a mapping from the virtual location to the physical location on the persistent storage device.

15. The method of claim 14 , further comprising:

recording a block corresponding to the previous physical location as dirty.

16. The method of claim 1 , further comprising:

writing a duplicate of the data to a subsequent physical location.

17. A system comprising:

one or more processors; and

a memory;

wherein the memory comprises instructions which, when executed by the one or more processors, configure the one or more processors to perform the method of claim 1 .

18. One or more non-transitory computer readable media comprising instructions which, when executed by one or more processors, cause the one or more processors to perform the method of claim 1 .