Load balancing of data reads in storage environments

摘要

Exemplary method, system, and computer program product embodiments for, within a data storage system performing data mirroring, performing load balancing pursuant to completing a read request. At least one of a preferred storage controller and preferred storage device to accommodate the read request is determined by performing one of selecting a request queue having a closest offset to an offset of the read request, selecting a request queue having a most requests within a predetermined distance of the offset of the read request, selecting a request queue having a closest median offset to the offset of the read request, selecting a request queue having a closest average offset to the offset of the read request, and selecting a request queue having a predetermined additional number of entries than another request queue. The selected request queue is associated with the preferred storage controller and the preferred storage device.

主权项

1. A method within a data storage system performing data mirroring for performing load balancing pursuant to completing a read request, comprising:
examining each request queue in the data storage system performing the data mirroring; determining at least one of a preferred storage controller and preferred storage device to accommodate the read request by performing one of:
selecting a request queue having a closest offset to an offset of the read request,selecting a request queue having a most requests within a predetermined distance of the offset of the read request,selecting a request queue having a closest average offset to the offset of the read request; wherein the selected request queue is associated with the at least one of the preferred storage controller and preferred storage device, wherein the preferred storage device is at least one of a first storage device and a second storage device in the data storage system; determining if a difference between a number of read requests in a first request queue and a number of read requests in a second request queue exceeds a predetermined threshold; selecting which of the first and second request queues having a shortest number of read requests if the difference between the number of read requests in the first request queue and the number of read requests in the second request queue exceeds the predetermined threshold; if the difference between the number of read requests in the first request queue and the number of read requests in the second request queue does not exceed the predetermined threshold;
determining a number of input/output (I/O) operations adjacent to the read request for each of the first and the second storage device,
for each of a plurality of read requests, if a first difference between a first request queue of the first storage device and the offset of the read request is less than a predetermined address space, incrementing the number of I/O operations adjacent to the read request for the first storage device and determining if additional read requests are to be examined pursuant to the incrementing the number of I/O operations adjacent to the read request for the first storage device, wherein:if there are additional read requests to be examined pursuant to the incrementing the number of I/O operations adjacent to the read request for the first storage device:
incrementing the number of I/O operations adjacent to the read request for the second storage device if a second difference between a second request queue of the second storage device and the offset of the read request is less than the predetermined address space, andif there are no additional read requests to be examined pursuant to the incrementing the number of I/O operations adjacent to the read request for the first storage device:
selecting a storage controller associated with the first storage device as the preferred storage controller if the number of I/O operations adjacent to the read request for the first storage device exceeds the number of I/O operations adjacent to the read request for the second storage device, otherwise selecting a storage controller associated with the second storage device as the preferred storage.