Updating raid stripe parity calculations

1. A method comprising:

receiving, at a first set of solid state drives, a last portion of a redundant array of independent disks (RAID) stripe among multiple portions of the RAID stripe, wherein the RAID stripe includes multiple shards, and wherein each previous portion of the RAID stripe is written to the first set of solid state drives;

calculating a current parity value based on the last portion of the RAID stripe and a previous parity value updated after receiving each previous portion of the RAID stripe; and

responsive to receiving all portions of a shard of the RAID stripe, copying the shard of the RAID stripe from the first set of solid state drives to a second set of solid state drives.

2. The method of claim 1 , wherein the current parity value represents parity data for each previous portion of the RAID stripe.

3. The method of claim 2 , wherein each portion of the RAID stripe defines a distinct portion of a shard of the RAID stripe.

4. The method of claim 1 , wherein each portion of the RAID stripe is written to a respective memory space that does not overlap with a memory space for another portion of the RAID stripe.

5. The method of claim 1 , wherein each portion of the RAID stripe is written to a memory location within one or more first memory components of the first set of solid state drives, and wherein the one or more first memory components are addressable by a first quantity of bytes.

6. The method of claim 5 , wherein copying the shard of the RAID stripe from the first set of solid state drives to the second set of solid state drives comprises:

copying the shard of the RAID stripe from one or more first memory components of the first set of solid state drives to a second memory component of the second set of solid state drives.

7. The method of claim 6 , wherein the second memory component of the second set of solid state drives is addressable by a second quantity of bytes that are different from the first quantity of bytes.

8. The method of claim 7 , wherein the one or more first memory components comprise nonvolatile RAM, and wherein the second memory component comprises flash memory.

9. The method of claim 1 , further comprising:

responsive to successfully writing the first portion of the RAID stripe: writing a corresponding status indication to a register of a solid state drive implementing a block addressable flash memory.

10. The method of claim 1 , further comprising:

responsive to successfully writing the first portion of the RAID stripe: writing a corresponding status indication to a metadata header for a different RAID stripe.

11. An apparatus comprising a computer processor, a computer memory operatively coupled to the computer processor, the computer memory having disposed within it computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:

receiving, at a first set of solid state drives, a last portion of a redundant array of independent disks (RAID) stripe among multiple portions of the RAID stripe, wherein the RAID stripe includes multiple shards, and wherein each previous portion of the RAID stripe is written to the first set of solid state drives;

calculating a current parity value based on the last portion of the RAID stripe and a previous parity value updated after receiving each previous portion of the RAID stripe; and

responsive to receiving all portions of a shard of the RAID stripe, copying the shard of the RAID stripe from the first set of solid state drives to a second set of solid state drives.

12. The apparatus of claim 11 , wherein the current parity value represents parity data for each previous portion of the RAID stripe.

13. The apparatus of claim 12 , wherein each portion of data of the RAID stripe defines a distinct portion of a shard of the RAID stripe.

14. The apparatus of claim 11 , wherein each portion of data of the RAID stripe is written to a respective memory space that does not overlap with a memory space for another portion of the RAID stripe.

15. The apparatus of claim 11 , wherein each portion of data of the RAID stripe is written to a memory location within one or more first memory components of the first set of solid state drives, and wherein the one or more first memory components are addressable by a first quantity of bytes.

16. The apparatus of claim 15 , wherein copying the shard of the RAID stripe from the first set of solid state drives to the second set of solid state drives comprises:

copying the shard of the RAID stripe from one or more first memory components of the first set of solid state drives to a second memory component of the second set of solid state drives.

17. The apparatus of claim 16 , wherein the second memory component of the second set of solid state drives is addressable by a second quantity of bytes that are different from the first quantity of bytes.

18. The apparatus of claim 17 , wherein the one or more first memory components comprise nonvolatile RAM, and wherein the second memory component comprises flash memory.

19. The apparatus of claim 11 , further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:

responsive to successfully writing the first portion of the RAID stripe: writing a corresponding status indication to a register of a solid state drive implementing a block addressable flash memory.

20. The apparatus of claim 11 , further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:

responsive to successfully writing the first portion of the RAID stripe: writing a corresponding status indication to a metadata header for a different RAID stripe.