Method for accelerating disk array write operations using segmented cache memory and data logging

TLDR: In this article, a cache-extension disk region is used to expand the size of the log structured cache by partitioning the cache memory region into write cache segments and redundancy data (parity) cache segments.

Abstract: Method and apparatus for accelerating write operations logging write requests in a log structured cache and by expanding the log structured cache using a cache-extension disk region The log structured cache include a cache memory region partitioned into one or more write cache segments and one or more redundancy-data (parity) cache segments The cache-extension disk region is a portion of a disk array separate from a main disk region The cache-extension disk region is also partitioned into segments and is used to extend the size of the log structured cache The main disk region is instead managed in accordance with storage management techniques (eg, RAID storage management) The write cache segment is partitioned into multiple write cache segments so that when one is full another can be used to handle new write requests When one of these multiple write cache segments is filled, it is moved to the cache-extension disk region thereby freeing the write cache segment for reuse The redundancy-data (parity) cache segment holds redundancy data for recent write requests, thereby assuring integrity of the logged write request data in the log structured cache