Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
1998-08-13
2002-04-02
Yoo, Do Hyun (Department: 2187)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S161000, C711S165000, C711S112000, C711S114000
Reexamination Certificate
active
06366987
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to computer data storage backup, and more particularly, to a data storage system that provides backup of physical storage units with a minimum of host computer system involvement.
BACKGROUND OF THE INVENTION
Due to advances in computer technology, there has been an ever-increasing need for data storage in data processing networks. In a typical data processing network, there has been an increase in the number of volumes of data storage and an increase in the number of hosts needing access to the volumes. This has been especially true for networks of workstations. Not only have a greater number of workstations been added to the typical network, but also the increase in data processing capabilities of a typical workstation has required more data storage per workstation for enhanced graphics and video applications.
Fortunately for computer users, the cost of data storage has continued to decrease at a rate approximating the increase in need for storage. For example, economical and reliable data storage in a data network can be provided by a storage subsystem including a Redundant Array of Independent Disks (RAID). Presently it is practical to provide a single data storage subsystem with up to 20 terabytes (TB) of storage, or approximately 4000 logical volumes, using magnetic disk drives each having a storage capacity of 46 gigabytes.
Unfortunately for network administrators, the development of services for storage management has lagged behind the increase in storage to be managed. Consequently, the cost of storage management has become relatively more significant. More troubling is the difficulty of maintaining the same level of management service as the amount of storage increases. For example, users are accustomed to being provided with backup and restore services for their data that is stored on the network. Users are encouraged to store their data on the network so that it can be shared by other authorized users and maintained in a cost-effective manner in accordance with corporate document retention policies. However, data stored on the network is always subject to some chance of loss due to a severe failure of the data storage system. Backup and restore services are a conventional way of reducing the impact of data loss from the network storage. To be effective, however, the data should be backed up frequently, and the data should be restored rapidly from backup after the storage system failure. As the amount of storage on the network increases, it is more difficult to maintain the frequency of the data backups, and to restore the data rapidly after a storage system failure.
SUMMARY OF THE INVENTION
In accordance with a first aspect, the invention provides a backup and restore method for use in a data processing system including a primary data storage subsystem and a secondary data storage subsystem. The method backs up and restores a logical data structure including a series of physical storage components. The method includes responding to a backup request for backup of the logical data structure, and responding to a restore request for restoring the logical data structure. In response to the back-up request, the method includes selecting a physical storage unit containing the logical data structure, and sending a backup command to the primary data storage subsystem for backing up the physical storage unit by copying a current version of the physical storage unit from primary storage in the primary data storage subsystem to the secondary data storage subsystem to create a backup version of the physical storage unit in secondary storage in the secondary data storage subsystem. In response to the restore request, the method includes issuing a restore command to the primary data storage subsystem for writing the backup version of the physical storage unit from the secondary storage to spare storage, and extracting the logical data structure from the spare storage by performing a logical-to-physical translation to identify the physical storage components of the logical data structure in the spare storage, and by copying the physical storage components of the logical data structure out from the spare storage to create a current version of the logical data structure in the primary storage of the primary data storage subsystem.
In accordance with another aspect, the invention provides a backup method for use in a data processing system including a primary data storage subsystem and a secondary data storage subsystem. The method backs up a logical data structure including a series of physical storage components. The method includes responding to a backup request for backup of the logical data structure by selecting a physical storage unit containing the logical data structure, and sending a backup command to the primary data storage subsystem. The method includes the primary data storage subsystem responding to receipt of the backup command by copying a current version of the physical storage unit from primary storage in the primary data storage subsystem to the secondary data storage subsystem to create a backup version of the physical storage unit in secondary storage in the secondary data storage subsystem. The method includes the secondary data storage subsystem responding to receipt of the backup version of the physical storage unit from the primary data storage subsystem by the secondary data storage subsystem compacting the physical storage unit for storage in the secondary storage by not writing to secondary storage a contiguous unused portion of the physical storage unit received from the primary data storage subsystem.
In accordance with yet another aspect, the invention provides a backup and restore method for use in a data processing system including a primary data storage subsystem and a secondary data storage subsystem. The method backs up and restores a logical data structure including a series of physical storage components. The method includes responding to a backup request for backup of the logical data structure, and responding to a restore request for restoring the logical data structure. In response to the back-up request, the method includes selecting a physical storage unit containing the logical data structure, and sending a backup command to the primary data storage subsystem for backing up the physical storage unit by copying a current version of the physical storage unit from primary storage in the primary data storage subsystem to the secondary data storage subsystem to create a backup version of the physical storage unit in secondary storage in the secondary data storage subsystem; and creating a catalog of information about logical data structures contained in the physical storage unit. In response to a restore request for restoring the logical data structure, the method includes accessing the catalog of information about logical data structures contained in the physical storage unit, in order to obtain information about the logical data structure, and using the information about the logical data structure for restoring the logical data structure from the backup version of the physical storage unit.
In accordance with still another aspect, the invention provides a backup and restore method for use in a data processing system including a data storage system having primary storage and secondary storage for storing backup versions of data stored in the primary storage. The method backs up a physical storage unit containing a logical data structure including a series of physical storage components, and restores the logical data structure from the backed-up physical storage unit. The method includes sending a backup command to the data storage system for backing up the physical storage unit by copying a current version of the physical storage unit from the primary storage to the secondary storage to create a backup version of the physical storage unit in the secondary storage, and creating a catalog of information about logical data structures contained in the backed-up version of the physical
Dunham Scott R.
Tzelnic Percy
EMC Corporation
Howrey Simon Arnold & White , LLP
Namazi Meheli
Yoo Do Hyun
LandOfFree
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