Multi-tier storage and mirrored volumes

1. A computer-implemented method comprising:

identifying a first data extent for promotion, wherein the first data extent is stored in a first storage pool of a multi-tier storage system (MTSS), based on a read-write heat mapping by the MTSS, wherein:

the first data extent is associated with a mirrored volume;

the first data extent is a mirrored copy of a second data extent stored in a second storage pool of the MTSS; and

the first storage pool is asymmetric to the second storage pool;

determining that a second top promotion tier of the second storage pool is faster than a first top promotion tier of the first storage pool;

promoting the second data extent to the second top promotion tier based on the determination; and

updating an I/O access policy to direct future I/O operations for the mirrored volume to the second data extent.

2. The method of claim 1 , wherein the first data extent is read-intensive, wherein the first top promotion tier does not comprise a read-intensive storage, and wherein the second top promotion tier comprises the read-intensive storage.

3. The method of claim 2 , wherein identifying the first data extent comprises determining that a number of READ operations performed on the read-intensive data extent exceeds a predetermined threshold.

4. The method of claim 3 , wherein identifying the first data extent comprises determining that a percentage of READ operations performed on the read-intensive data extent exceeds a predetermined threshold, wherein the percentage of READ operations comprises a number of the READ operations performed on the first data extent divided by a total number of I/O access operations performed on the first data extent.

5. The method of claim 1 , wherein the first storage pool comprises a first bottom storage tier.

6. The method of claim 5 , wherein the first bottom storage tier is a cloud backup.

7. The method of claim 1 , wherein the second top promotion tier provides faster I/O access than the first top promotion tier.

8. The method of claim 1 , further comprising:

receiving a READ operation request for the mirrored volume; and

performing a READ operation of the second data extent in the second top promotion tier.

9. The method of claim 1 , further comprising:

demoting the second data extent from the second top storage tier; and

updating the I/O access policy to direct future I/O operations for the mirrored volume to the first data extent.

10. A computer program product comprising program instructions stored on a computer readable storage medium, wherein the computer readable storage medium is not a transitory signal per se, the program instructions executable by a processor to cause the processor to perform a method comprising:

identifying a first data extent for promotion, wherein the first data extent is stored in a first storage pool of a multi-tier storage system (MTSS), based on a read-write heat mapping by the MTSS, wherein:

the first data extent is a mirrored copy of a second data extent stored in a second storage pool of the MTSS;

the first storage pool is asymmetric to the second storage pool;

the first data extent is read-intensive;

identifying the first data extent comprises determining that a number of READ operations performed on the read-intensive data extent exceeds a predetermined threshold the first data extent is associated with a mirrored volume;

determining that a second top promotion tier of the second storage pool is faster than a first top promotion tier of the first storage pool, wherein the second top promotion tier comprises read-intensive storage;

promoting the second data extent to the second top promotion tier based on the determination; and

updating an I/O access policy to direct future I/O operations for the mirrored volume to the second data extent.

11. The computer program product of claim 10 , wherein identifying the first data extent comprises determining that a percentage of READ operations performed on the read-intensive data extent exceeds a predetermined threshold, wherein the percentage of READ operations comprises a number of the READ operations performed on the first data extent divided by a total number of I/O access operations performed on the first data extent, and wherein the first top promotion tier does not comprise the read-intensive storage.

12. The computer program product of claim 10 , wherein the first storage pool comprises a first bottom storage tier.

13. The computer program product of claim 12 , wherein the first bottom storage tier is a cloud backup.

14. The computer program product of claim 10 , wherein the second top promotion tier provides faster I/O access than the first top promotion tier.

15. The computer program product of claim 10 , the method further comprising:

receiving a READ operation request for the mirrored volume; and

performing a READ operation of the second data extent in the second top promotion tier.

16. The computer program product of claim 10 , the method further comprising:

demoting the second data extent from the second top storage tier; and

updating the I/O access policy to direct future I/O operations for the mirrored volume to the first data extent.

17. A system comprising:

a computer processing circuit; and

a computer-readable storage medium storing instructions, which, when executed by the computer processing circuit, are configured to cause the computer processing circuit to perform a method comprising:

identifying a first data extent for promotion, wherein the first data extent is stored in a first storage pool of a multi-tier storage system (MTSS), based on a read-write heat mapping by the MTSS, wherein:

the first data extent is a mirrored copy of a second data extent stored in a second storage pool of the MTSS;

the first storage pool is asymmetric to the second storage pool;

the first data extent is read-intensive;

identifying the first data extent comprises:

determining that a number of READ operations performed on the read-intensive data extent exceeds a predetermined threshold the first data extent is associated with a mirrored volume; and

determining that a percentage of READ operations performed on the read-intensive data extent exceeds a predetermined threshold, wherein the percentage of READ operations comprises a number of the READ operations performed on the first data extent divided by a total number of I/O access operations performed on the first data extent;

determining that a second top promotion tier of the second storage pool is faster than a first top promotion tier of the first storage pool, wherein the second top promotion tier comprises read-intensive storage;

promoting the second data extent to the second top promotion tier based on the determination; and

updating an I/O access policy to direct future I/O operations for the mirrored volume to the second data extent.

18. The system of claim 17 , wherein the second top promotion tier provides faster I/O access than the first top promotion tier, and wherein the first top promotion tier does not comprise the read-intensive storage.

19. The system of claim 17 , the method further comprising:

receiving a READ operation request for the mirrored volume; and

performing a READ operation of the second data extent in the second top promotion tier.

20. The system of claim 17 , the method further comprising:

demoting the second data extent from the second top storage tier; and

updating the I/O access policy to direct future I/O operations for the mirrored volume to the first data extent.