International Business Machines Corporation

John G Aschoff

Bruce McNutt

David Darden Chambliss

David Alan Burton

Jeffrey Allen Berger

Stanley C Kurtz

A data storage system comprising a Quality of Service server to optimize revenue realized under multiple service level agreements with a data storage client.

Data storage system to optimize revenue realized under multiple service level agreements

A method to optimize revenue realized under multiple service level agreements with multiple data storage clients is disclosed. The method provides an information storage and retrieval system. The method includes entering into (N) service level agreements to provide data storage services for (N) applications using the information storage and retrieval system, where each of the (N) service level agreements specifies an average maximum response time RT. The method calculates for each value of (j), the value per unit throughput &#x3bd;for the (j)th application, and then determines for each value of (j) the optimum data flow rate x. The method estimates, for each value of (j), a maximum data flow rate Xthat the (j)th application can utilize, and determines, for each value of (j), if xequals X. For each value of (j) where xdoes not equal X, the method delays execution of I/O requests from the (j)th application, such that the average response time for the (j)th application equals RT.

Apparatus and method to optimize revenue realized under multiple service level agreements

Dynamic allocation of read cache space is allocated among bands of DASD cylinders rather than to data sets or processes as a function of a weighted average hit ratio to the counterpart cache space. Upon the hit ratio falling below a predetermined threshold, the bands are disabled for a defined interval as measured by cache accesses and then rebound to cache space again.

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Watsonville, CA, United States of America

John G Aschoff