Patent ID: 7035971

Claim:
A storage arrangement for processing storage requests that are part of workloads having different quality-of-service requirements, comprising: a plurality of storage arrays configured for storage of a replicated data set, wherein at least two of the storage arrays have unequal performance levels for processing storage requests; a controller coupled to the storage arrays, the controller configured to monitor actual performance levels provided by the storage arrays in processing storage requests, distribute storage requests between the storage arrays as a function of quality-of-service requirements of the workloads and the performance levels provided by the storage arrays, determine a first performance level for a first storage array of the plurality of storage arrays and a second performance level for a second storage array of the plurality of storage arrays, and responsive to the first performance level being greater than a first quality of service requirement of a first type of workload, distribute all storage requests of the first type of workload to the first storage array, wherein the quality-of-service requirements are bounds on response times, and the performance levels are response times.