Patent ID: 7546434

Claim:
A method to write data to an information storage and retrieval system comprising (n) volumes and a data cache, wherein said information storage and retrieval system is capable of communicating with one or more host computers, comprising the steps of: establishing (n) maximum delays, wherein each of said (n) maximum delays is associated with a different one of said (n) volumes, and wherein an (i)th maximum delay is set by a host computer writing data to an (i)th volume, wherein (i) is greater than or equal to 1 and less than or equal to (n); receiving from a host computer an update for an (i)th volume; determining an (i)th delay, wherein the (i)th delay is associated with the (i)th volume; writing said update to said data cache interposing said (i)th delay without making said information storage and retrieval system unavailable to said one or more host computers establishing (m) delay levels, wherein each of said (m) delay levels is associated with a different interposed delay; operative if an (i)th volume update count is not greater than or equal to an (i)th volume update threshold, setting an (i)th delay level, wherein said (i)th delay level comprises one of said (m) delay levels, and wherein the (i)th volume update count comprises the number of sidefiles associated with the (i)th volume written to the data cache; establishing an (i)th maximum delay level, wherein said (i)th maximum delay level comprises one of said (m) delay levels; wherein said setting the (i)th delay level step comprises: calculating a pacing interval by dividing said (i)th volume update threshold by said (i)th maximum delay level; calculating the (i)th delay level by dividing using integer truncation said (i)th volume update count by said pacing interval.