Method and apparatus for processing read requests in a shared disk system

摘要

A shared device environment having multiple nodes (4a-4c), each node containing a computer (6a-6c), an adaptor (8a-8c) and multiple storage devices (10a-10c). Adaptors (8a-8c) facilitate read access to storage devices (10a-10c) such that the data records accessed are the latest version data records. Adaptors (8a-8c) are operative to provide the latest version of data blocks requested by computers (6a-6c) by first searching the read cache of each adaptor for data blocks requested by computers (6a-6c). If the requested data blocks are not found in the read cache of any adaptors, then data structures (155, 156 and 158) within the adaptors are searched for any data blocks waiting to be added to the read cache of any adaptors. If no data blocks are found, then the read access is conducted directly from the storage device itself.