Patent ID: 7356643

Claim:
A method for managing a storage server comprising first and second clusters of storage controllers, said first cluster comprising one or more storage controllers each controlling one or more storage arrays, said first cluster also comprising a first cache memory and a first nonvolatile storage (â€œNVSâ€) shared by said one or more storage controllers of said first cluster, said second cluster comprising one or more storage controllers each controlling one or more storage arrays, said second cluster also comprising a second cache memory and a second nonvolatile storage shared by said one or more storage controllers of said second cluster, said method comprising the steps of: monitoring an amount of time that data controlled by each of said clusters is held in the cache memory of said each cluster before being outpaged to said storage arrays; monitoring an amount of requests to access storage arrays of a cluster that were delayed due to insufficient NVS; and determining a level of impairment of access to each of said storage arrays based on the amount of time that data controlled by each of said clusters was held in the cache memory of said each cluster before being outpaged to said storage arrays, and the amount of requests to access the storage arrays of a cluster that were delayed due to insufficient NVS.