Managing write requests for drives in cloud storage systems

1. A system comprising:

a processor; and

a memory including instructions that are executable by the processor for causing the processor to:

receive a plurality of write requests for writing a first set of data to a first drive of a plurality of drives, the first drive being powered off;

in response to receiving the plurality of write requests, write the first set of data to a cache;

determine that a number of the plurality of write requests exceeds a predetermined write request threshold or that a storage amount in the cache exceeds a predetermined storage threshold;

in response to determining that the number of the plurality of write requests exceeds the predetermined write request threshold or that the storage amount exceeds the predetermined storage threshold, write the first set of data stored in the cache to a second drive of the plurality of drives, the second drive being powered on;

determine that the first drive is powered on; and

in response to determining that the first drive is powered on, write the first set of data stored in the second drive to the first drive.

2. The system of claim 1 , wherein the memory further comprises instructions that are executable by the processor for causing the processor to:

in response to determining that the number of the plurality of write requests exceeds the predetermined write request threshold or that the storage amount in the cache exceeds the predetermined storage threshold, power on the first drive; and

write the first set of data stored in the cache or the second drive to the first drive.

3. The system of claim 1 , wherein the cache is a battery-backed cache or a non-volatile random-access memory.

4. The system of claim 1 , wherein the memory further comprises instructions that are executable by the processor for causing the processor to:

receive a read request for reading a second set of data from the first drive;

in response to receiving the read request, power on the first drive for reading the second set of data from the first drive; and

write the first set of data stored in the cache to the first drive.

5. The system of claim 4 , wherein the memory further comprises instructions that are executable by the processor for causing the processor to:

determine that the first drive is powered off; and

disable a prefetching operation for prefetching the second set of data from the first drive to be written to the cache prior to receiving a read request for reading the second set of data from the first drive.

6. The system of claim 4 , wherein the memory further comprises instructions that are executable by the processor for causing the processor to:

determine that the first drive is powered on; and

enable a prefetching operation for prefetching the second set of data from the first drive to be written to the cache prior to receiving a read request for reading the second set of data from the first drive.

7. A method comprising:

receiving, by a processor, a plurality of write requests for writing a first set of data to a first drive of a plurality of drives, the first drive being powered off;

in response to receiving the plurality of write requests, writing, by the processor, the first set of data to a cache;

determining, by the processor, that a number of the plurality of write requests exceeds a predetermined write request threshold or that a storage amount in the cache exceeds a predetermined storage threshold;

in response to determining that the number of the plurality of write requests exceeds the predetermined write request threshold or that the storage amount exceeds the predetermined storage threshold, writing, by the processor, the first set of data stored in the cache to a second drive of the plurality of drives, the second drive being powered on;

determine that the first drive is powered on; and

in response to determining that the first drive is powered on, writing, by the processor, the first set of data stored in the second drive to the first drive.

8. The method of claim 7 , further comprising:

in response to determining that the number of the plurality of write requests exceeds the predetermined write request threshold or that the storage amount in the cache exceeds the predetermined storage threshold, powering on the first drive; and

writing the first set of data stored in the cache or the second drive to the first drive.

9. The method of claim 7 , wherein the cache is a battery-backed cache or a non-volatile random-access memory.

10. The method of claim 7 , further comprising:

receiving a read request for reading a second set of data from the first drive;

in response to receiving the read request, powering on the first drive for reading the second set of data from the first drive; and

writing the first set of data stored in the cache to the first drive.

11. The method of claim 10 , further comprising:

determining that the first drive is powered off; and

disabling a prefetching operation for prefetching the second set of data from the first drive to be written to the cache prior to receiving a read request for reading the second set of data from the first drive.

12. The method of claim 10 , further comprising:

determining that the first drive is powered on; and

enabling a prefetching operation for prefetching the second set of data from the first drive to be written to the cache prior to receiving a read request for reading the second set of data from the first drive.

13. A non-transitory computer-readable medium comprising program code that is executable by a processor for causing the processor to:

receive a plurality of write requests for writing a first set of data to a first drive of a plurality of drives, the first drive being powered off;

in response to receiving the plurality of write requests, write the first set of data to a cache;

determine that a number of the plurality of write requests exceeds a predetermined write request threshold or that a storage amount in the cache exceeds a predetermined storage threshold;

in response to determining that the number of the plurality of write requests exceeds the predetermined write request threshold or that the storage amount exceeds the predetermined storage threshold, write the first set of data stored in the cache to a second drive of the plurality of drives, the second drive being powered on;

determine that the first drive is powered on; and

in response to determining that the first drive is powered on, write the first set of data stored in the second drive to the first drive.

14. The non-transitory computer-readable medium of claim 13 , further comprising program code that is executable by the processor for causing the processor to:

in response to determining that the number of the plurality of write requests exceeds the predetermined write request threshold or that the storage amount in the cache exceeds the predetermined storage threshold, power on the first drive; and

write the first set of data stored in the cache or the second drive to the first drive.

15. The non-transitory computer-readable medium of claim 13 , wherein the cache is a battery-backed cache or a non-volatile random-access memory.

16. The non-transitory computer-readable medium of claim 13 , further comprising program code that is executable by the processor for causing the processor to:

receive a read request for reading a second set of data from the first drive;

in response to receiving the read request, power on the first drive for reading the second set of data from the first drive; and

write the first set of data stored in the cache to the first drive.

17. The non-transitory computer-readable medium of claim 16 , further comprising program code that is executable by the processor for causing the processor to:

determine that the first drive is powered off; and

disable a prefetching operation for prefetching the second set of data from the first drive to be written to the cache prior to receiving a read request for reading the second set of data from the first drive.