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Adaptive Dump to Disk proceess based on available battery capacity

IP.com Disclosure Number: IPCOM000032689D
Original Publication Date: 2004-Nov-10
Included in the Prior Art Database: 2004-Nov-10
Document File: 1 page(s) / 25K

Publishing Venue

IBM

Abstract

Method to adapt the modified data journal storage process, in a data storage subsystem, to maintain data protection in the event of a diminished capacity battery system. By adapting the process the system is able to operate in a number of scenarios that would normally cause the system to be unavailable

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Adaptive Dump to Disk proceess based on available battery capacity

     Disclosed is a method to maintain data storage subsystem function in the event of a diminished capacity battery system. Data storage subsytems typically defer writes to the physical media to improve performance of the system write operation. The data is staged for write to the media in a cache memory structure. The data modification is also stored in a battery backed journal memory. Current redundant data controller subsystems are comprised of two clusters each with a data cache and a battery backed journal for its partner cluster. In this fashion all modified data is still available even in the event of a cluster failure.

     In a power failure scenario the clusters store their journal memory in a non-volatile location as well as pulling across its partners journal memory, resulting in two separate copies of the modified data to ensure recovery at resumption of power to the system. A partial fail or loss of a portion of the battery capacity for one of the journal memories results in a cluster failure and all the activity must be handled by the surviving cluster. In order to maintain a better level of redundancy for system operation, as well as maintaining system performance, a modification of the journal hardening process is used.

     Battery status and capacity are tested and monitored on a regular basis. The stored power required to store the journal structures to disk, as well as copy the structures f...