Data storage system recovery from disk failure during system off-line condition

摘要

A method for returning a logical volume which is part of a redundant data storage system to on-line status following a disk failure within the logical volume during the time when another of that volume's disks is unavailable as a result of having its firmware updated, as an example. Data which would otherwise be changed in the logical volume due to host write requests is directed to a logging facility within the data storage system, but outside of the logical volume undergoing upgrade.