Emc Corporation

Richard G Chandler

Sorin Faibish

Uday K Gupta

David W Harvey

Xiaoye Jiang

Stephen A Fridella

Hongliang Tang

H Austin Spang, Iv

Described are techniques for performing caching. Write operations of a single transactions are received. Write data of the write operations is cached in one or more cache pages of a first cache of a first storage processor. State information is set for the one or more cache pages of the first cache from an invalid state to a prepared state. The write data of the write operations is also stored in a second cache of a second storage processor. A transaction commit state for the single transaction is set indicating that transaction commitment processing for the first cache has commenced and is pending. State information of the one or more cache pages of the first cache is set from the prepared state to a dirty state. The transaction commit state for the single transaction is updated to indicate that the transaction commitment processing for the first cache is completed.

Techniques for maintaining and restoring dirty caches across CPU resets

A read-write access to a file in a file server includes an initial metadata access step, an asynchronous read or write of file data, and a metadata commit step. In order to parallelize access to a range locking database, an inode and indirect file block mapping database, and a pre-allocation data base, operations are pipelined within the metadata access step and also within the metadata commit step. The pipelined operations within the metadata access step include a first stage of range locking, a second stage of reading block mapping metadata, and a third stage of reading and updating a pre-allocation map for write access. The pipelined operations within the metadata commit step include a first stage of releasing range locks, a second stage of accessing old block metadata for write access, and a third stage of updating metadata and flushing the pre-allocation map for write access.

Metadata pipelining and optimization in a file server

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West Hartford, CT, United States of America

Richard G Chandler