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Abstract

A method and apparatus for using undo/redo logging to perform asynchronous updates of parity and data pages in a redundant array data storage system is disclosed. The computer-implemented apparatus includes, 1) a redundant array data storage system having a plurality of data pages and a corresponding parity page residing therein, each page of the plurality of data pages and the parity page containing version information indicating a version of content in the page, 2) a memory-resident plurality of data pages corresponding to the plurality of data pages residing in the redundant array data storage system, 3) a data log retaining modification information defining any differences between content of the memory-resident plurality of data pages and content of the plurality of data pages residing in the redundant array data storage system, and 4) control logic for deferring modification of the parity page following modification of one of the plurality of data pages. The control logic further includes control logic for re-creating content of one of the plurality of data pages or the parity page by applying the modification information in the data log to the memory-resident plurality of data pages.

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First Claim