Patent ID: 6076148
Filing Date: 2000-06-13
Classification: G06F

Abstract:
A mass storage subsystem comprising:A. at least one storage device configured to store information in a plurality of storage blocks;B. a backup status table including a plurality of backup status indicators each associated with one of the storage blocks, each backup status indicator comprising a series of snapshot flags, each snapshot flag associated with one of a plurality of snapshots of information stored on said storage device, each snapshot flag having a snapshot backup state if the associated storage block is to be backed up as a snapshot during a backup operation, and a second state;C. a backup interface configured to:i. sequence through the block backup status table and perform a backup operation in connection with respective storage blocks whose associated snapshot flags are in the backup state; andii. in response to a backup request in connection with a respective one of said storage blocks, perform a backup operation in connection therewith; the backup interface being further configured to, as respective storage blocks are backed up during the backup operation,iii. transfer, along with the information from respective storage blocks, the respective backup status indicator associated therewith, to the backup subsystem, andiv. condition the snapshot flags associated therewith to the second state; andD. a host interface configured to, prior to storing information on said storage device, use the block status table to determine whether the backup status indicator associated with one of said storage blocks in which the information is to be stored has a snapshot flag in the backup state and, if so, generate said backup request for provision to said backup interface.