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AssigneeEMC Corporation
InventorNadav Kedem
Estimating the term…
A computer system includes a host computer, a mass storage subsystem and a backup subsystem for backing up information stored on the mass storage subsystem. The mass storage subsystem stores information on a series of tracks. A backup bit map includes a plurality of bits each associated with a respective one of the tracks and indicates the backup status of the track during a backup operation. Initially, during a backup operation, the bits associated with the tracks to be backed up will be set. Generally, the mass storage subsystem transfers information from the track to be backed up in order of the bits in the bit map, and after each track is backed up, it will clear the track's bit. However, when the host is to store information in the mass storage subsystem, it will determine whether the bit associated with the track in which the information is to be stored is set and, if so, enable the mass storage subsystem to back up the track out of turn, and to re-set the track's bit. After the information has been retrieved from the track, the bit associated therewith will be reset, and the host will store the information in the track. This allows the mass storage subsystem to ensure that the backed up information will correspond to the information as of the beginning of the backup operation, and in addition will allow the host to continue operations during the backup operation.
A mass storage subsystem comprising:
A backup subsystem configured to back up information stored on a mass storage subsystem, to provide a plurality of snapshots of the information stored on the mass storage subsystem, the backup subsystem comprising:
A backup subsystem configured to backup information stored on a mass storage subsystem, the information being stored on the mass storage subsystem in a plurality of storage blocks associated with respective ones of a series of block identifiers, the backup subsystem comprising at least one backup storage device, a buffer, and a backup control, the backup control being configured to allocate at least one cell in said buffer for storing information from the storage blocks received from said backup interface associated with a sequence of block identifiers in said cell thereby to buffer said information in the buffer, and to enable the information in the cell to be transferred to the backup storage device after information from all of the storage blocks associated with the cell has been received.
A method of controlling a mass storage subsystem comprising at least one storage device configured to store information in a plurality of storage blocks and 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, the method comprising the steps of
A method of controlling a backup subsystem to back up information stored on a mass storage subsystem to provide a plurality of snapshots of the information stored on the mass storage subsystem, the backup subsystem including a plurality of backup storage devices each configured to store information for one of said snapshots;
A method of controlling backup subsystem configured to backup information stored on a mass storage subsystem, the information being stored on the mass storage subsystem in a plurality of storage blocks associated with respective ones of a series of block identifiers, the method comprising the steps of:
Dependencies are inferred from the claim text.