LOGICAL VOLUME CONFIGURATION DATA MANAGEMENT DETERMINES WHETHER TO EXPOSE THE LOGICAL VOLUME ON-LINE, OFF-LINE REQUEST BASED ON COMPARISON OF VOLUME EPOCH NUMBERS ON EACH EXTENTS OF THE VOLUME IDENTIFIERS

摘要

Volume configuration data management systems and methods are described. A logical volume provider maintains an epoch number on each of the extents comprising a volume. Upon each change in the configuration of the volume, the epoch number on each of the currently online extents is updated. When a volume is discovered and a request is made to bring the volume online, the logical volume provider can compare the epoch numbers on the extents to determine if the volume data is consistent across each of the extents, or if an extent contains stale data due to a transitory outage.