Patent ID: 7596670

Claim:
A computer-implemented method for operating a data storage system having a plurality of memory caches linked to physical storage units and having enqueued requests for access to said physical storage units, said storage system being coupled multiple hosts, comprising the steps of: detecting a condition affecting one of said physical storage units, wherein a volume of pending access requests for access to said one physical storage unit exceeds a first threshold value; responsively to said step of detecting imposing a restriction on new requests for access to said storage system by the multiple hosts, the restriction comprising limiting a rate of acceptance of the new requests by establishing an alternating sequence of blocking intervals and non-blocking intervals for the new requests from all the hosts, wherein a blocking period of the blocking intervals and a non-blocking period of the non-blocking intervals are configured to prevent timeouts for all the hosts; thereafter determining that said volume has fallen below a second threshold value; and responsively to said step of determining, removing said restriction.