Remote control of backup media in a secondary storage subsystem through access to a primary storage subsystem

• US 6,353,878 B1
• Filed: 08/13/1998
• Issued: 03/05/2002
• Est. Priority Date: 08/13/1998
• Status: Expired due to Term

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Dunham, Scott R.
• Primary Examiner(s): NGUYEN, THAN VINH
• Application Number:
  US09/133,885
• Time in Patent Office: 1,300 Days
• Field of Search: 707/9, 707/10, 707/204, 711/4, 711/112, 711/114, 711/161, 711/162
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: Y10S 707/99939 Privileged access
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A primary data storage subsystem has primary data storage and a storage controller for controlling access of host processors to the primary data storage. The primary data storage subsystem is linked to a secondary data storage subsystem for transfer of backup data between the primary data storage subsystem and the secondary data storage subsystem. The secondary data storage subsystem has a tape library unit for storing the backup data. A host processor usually accesses the primary storage. A host can also send backup and restore commands to the storage controller, to cause specified data from the primary storage to be written as a backup version in the tape library unit, and to cause a specified backup version to be read from the tape library unit to be accessible to the host from the primary data storage unit. In this fashion, the host need not be concerned with the basic operations of the tape library unit. A host, however, can send backup media remote control requests to the storage controller, and the storage controller responds by sending corresponding backup media remote control commands to the tape library unit, to permit the host to control remotely the basic operations of the tape library unit. Therefore, the host can obtain status of read/write stations in the tape library unit, and control the mounting, unmounting, and transport of the tapes mounted at the read/write stations.

Claims

1. A method of operating a data storage system including a primary data storage subsystem and a secondary data storage subsystem linked to the primary data storage subsystem for transfer of backup data between the primary data storage subsystem and the secondary data storage subsystem, the primary data storage subsystem including a cached disk storage subsystem, the secondary data storage subsystem including a cached disk storage subsystem and a tape library unit for storage of the backup data, said method comprising:

a) the secondary data storage subsystem maintaining a directory of versions of backup data stored in the tape library unit;

b) the primary data storage subsystem receiving from a host processor a backup media remote control request;

c) the primary data storage subsystem sending to the secondary data storage subsystem a backup media remote control command corresponding to the backup media remote control request; and

d) the secondary data storage subsystem receiving the backup media remote control command, and the tape library unit executing the backup media remote control command.

2. The method as claimed in claim 1, which further includes returning an acknowledgment from the tape library unit to the host processor by the secondary data storage subsystem returning the acknowledgment to the primary data storage subsystem, and the primary data storage subsystem returning the acknowledgment to the host processor.

3. The method as claimed in claim 2, which includes the primary data storage subsystem receiving backup media remote control requests from a plurality of host processors, and returning an acknowledgment for each backup media remote control request from the tape library unit to the host processor which originated said each backup media remote control request.

4. The method as claimed in claim 1, which includes a plurality of host processors accessing the primary data storage subsystem sending backup media remote control requests to the primary data storage subsystem, and which includes the secondary data storage subsystem checking access rights of the host processors in order to deny access to a backup version that a host processor has no right to access.

5. The method as claimed in claim 1, wherein the primary data storage subsystem receives backup and restore commands from host processors in addition to backup media remote control requests, and in response to the backup and restore commands, the primary data storage subsystem accesses a directory of primary data storage and the secondary data storage subsystem accesses a directory of backup versions and tapes in order to generate commands to the tape library unit for executing the backup and restore commands.

6. The method as claimed in claim 1, which includes the primary data storage subsystem receiving from the host processor backup media remote control requests for mounting and unmounting specified tapes in a read/write station in the tape library unit, and for reading and writing to the tapes mounted in the read/write station, and in response the tape library unit mounting and unmounting the specified tapes in the read/write station in the tape library unit, and reading and writing to the tapes mounted in the read/write station.

7. The method as claimed in claim 1, which includes the host processor sending to the primary data storage subsystem a backup media remote control request for status information about a read/write station, and in response the tape library unit identifying a tape mounted in the read/write station, and reporting storage capacity of the tape, block size of data blocks stored on the tape, a current block number, and an amount of data storage space remaining on the tape.

8. The method as claimed in claim 1, which includes the primary data storage subsystem receiving from the host processor backup media remote control requests that include SCSI commands which are passed through the primary data storage subsystem and are executed by the tape library unit.

9. The method as claimed in claim 8, wherein the SCSI commands that are executed by the tape library unit include SCSI query commands that identify the read/stations in the tape library unit and that get state information about specified ones of the read/write stations.

10. The method as claimed in claim 8, wherein the SCSI commands that are executed by the tape library unit include SCSI commands that reset state of specified ones of the read/write stations.

11. A method of operating a data storage system including a primary data storage subsystem and a secondary data storage subsystem linked to the primary data storage subsystem for transfer of backup data between the primary data storage subsystem and the secondary data storage subsystem, the primary data storage subsystem including a cached disk storage subsystem, the secondary data storage subsystem including a cached disk storage subsystem and a tape library unit for storage of the backup data, said method comprising:

a) the secondary data storage subsystem maintaining a directory of versions of backup data stored in the tape library unit;

b) the primary data storage subsystem receiving from a first host processor a backup media remote control request;

the primary data storage subsystem sending to the secondary data storage subsystem a backup media remote control command corresponding to the backup media remote control request;

the secondary data storage subsystem receiving the backup media remote control command, and the tape library unit executing the backup media remote control command and returning an acknowledgment to the primary data storage subsystem, and the primary data storage subsystem returning the acknowledgment to the first host processor; and

c) the primary data storage subsystem receiving from a second host processor a backup request for backup of specified data in the primary data storage, and in response the primary data storage subsystem transmitting at least one command to the secondary data storage subsystem for storing a backup version of the specified data in tape storage in the tape library unit without requiring the second host processor to issue backup media remote control requests.

12. The method as claimed in claim 11, which includes the primary data storage subsystem receiving backup media remote control requests from a plurality of data processors, and which includes the secondary data storage subsystem checking access rights of the host processors in order to deny access to a backup version that a host processor has no right to access.

13. The method as claimed in claim 11, which includes the primary data storage subsystem receiving from the first host processor backup media remote control requests for mounting and unmounting specified tapes in a read/write station in the tape library unit, and for reading and writing to the tapes mounted in the read/write station, and in response the tape library unit mounting and unmounting the specified tapes in the read/write station in the tape library unit, and reading and writing to the tapes mounted in the read/write station.

14. The method as claimed in claim 11, which includes the primary data storage subsystem receiving from the first host processor backup media remote control requests for status information about a read/write station, and in response the tape library unit identifying a tape mounted in the read/write station, and reporting storage capacity of the tape, block size of blocks stored on the tape, a current block number, and an amount of data storage space remaining on the tape.

15. The method as claimed in claim 11, which includes the primary data storage subsystem receiving from the first host processor backup media remote control requests that include SCSI commands that are passed through the primary data storage subsystem and are executed by the tape library unit.

16. A data storage system comprising, in combination:

a primary data storage subsystem including primary data storage and a storage controller coupled to the primary data storage for controlling access to the primary data storage, the storage controller having at least one data port for coupling to at least one host processor for receiving data access commands from the host processor for access to the primary data storage;

the primary data storage including a primary cached disk storage subsystem, and

a secondary data storage subsystem linked to the storage controller of the primary data storage subsystem for transfer of backup data between the primary data storage subsystem and the secondary data storage subsystem, the secondary data storage subsystem including a tape library unit for storage of the backup data, and a secondary cached disk storage subsystem and at least one processor coupled to the tape library unit for buffering backup data transmitted between the primary data storage subsystem and the tape library unit and maintaining a directory of versions of backup data stored in the tape library unit;

wherein the storage controller of the primary data storage subsystem is programmed for receiving from the host processor a backup media remote control request, and sending to the secondary data storage subsystem a backup media remote control command corresponding to the backup media remote control request for execution of the backup media remote control command by the tape library unit.

17. The data storage system as claimed in claim 16, wherein the storage controller of the primary data storage subsystem is programmed to receive an acknowledgment of the backup media remote control command from the tape library unit of the secondary data storage subsystem, and to return the acknowledgment to the host processor.

18. The data storage system as claimed in claim 16, which includes a dedicated data link between the primary data storage subsystem and the secondary data storage subsystem for the transfer of the backup data between the primary data storage subsystem and the secondary data storage subsystem, the dedicated data link not being shared by any host processor for communication with the primary data storage subsystem or with the secondary data storage subsystem.

19. The data storage system as claimed in claim 16, wherein the storage controller of the primary data storage subsystem is programmed to receive backup media remote control requests from a plurality of host processors, and wherein the secondary data storage subsystem includes a secondary directory of tapes and backup versions stored in the tape library unit, and a processor coupled to the secondary directory and the tape library unit and programmed for checking access rights of the host processors in order to deny access to a backup version that a host processor has no right to access.

20. The data storage system as claimed in claim 16, wherein the storage controller of the primary data storage subsystem is programmed to receive from the host processor backup and restore requests in addition to the backup media remote control requests, and the storage controller is programmed to respond to the backup and restore requests by sending at least one command to the secondary data storage subsystem for writing specified data from the primary data storage to tape in the tape storage unit and reading specified backup versions from the tape in the tape storage unit.

21. The data storage system as claimed in claim 16, wherein the secondary data storage subsystem is responsive to backup media remote control commands for mounting and unmounting specified tapes in a read/write station in the tape library unit, and for reading and writing to the tapes mounted in the read/write station.

22. The data storage system as claimed in claim 16, wherein the secondary data storage subsystem is responsive to backup media remote control requests for status information about a read/write station including identification of a tape mounted in the read/write station, storage capacity of the tape, block size of blocks stored on the tape, a current block number, and an amount of data storage space remaining on the tape.

23. The data storage system as claimed in claim 16, wherein the storage controller of the primary data storage subsystem is programmed to receive from the host processor backup media remote control requests that include SCSI commands, and to pass the SCSI commands to the secondary data storage subsystem for execution by the tape library unit.

24. A data storage system comprising, in combination:

a primary data storage subsystem including primary data storage, a primary directory to information stored in the primary data storage, and a storage controller coupled to the primary data storage and the primary directory for controlling access to the primary data storage, the storage controller having at least one data port for coupling to a plurality of host processors for receiving data access commands from the host processors for access to the primary data storage; and

a secondary data storage subsystem linked to the storage controller of the primary data storage subsystem for transfer of backup data between the primary data storage subsystem and the secondary data storage subsystem, the secondary data storage subsystem including a tape library unit for storage of the backup data, a secondary directory to tapes in the tape library unit and backup versions stored on the tapes in the tape library unit, and a processor linking the secondary directory and the tape library unit for control of access to the tapes in the tape library unit;

wherein the storage controller of the primary data storage subsystem is programmed for receiving from the host processors backup media remote control requests, and sending to the secondary data storage subsystem backup media remote control commands corresponding to the backup media remote control requests for execution of the backup media remote control commands by the tape library unit, and for returning acknowledgments of the backup media remote control commands from the secondary data storage subsystem to the host processors, and

wherein the storage controller of the primary data storage subsystem is programmed for receiving from the host processors backup requests for backup of specified data in the primary data storage, and in response for transmitting commands to the secondary data storage subsystem for storing backup versions of the specified data in tape storage in the tape library unit without requiring the host processors to issue backup media remote control requests for storing the backup versions of the specified data in the tape storage of the tape library unit.

25. The data storage system as claimed in claim 24, wherein the data processor of the secondary data storage subsystem is programmed for checking access rights of the host processors in order to deny access to a backup version that a host processor has no right to access.

26. The data storage system as claimed in claim 24, wherein the secondary data storage subsystem includes disk storage coupled to the tape library unit for buffering backup data transmitted between the primary data storage subsystem and the tape library unit.

27. The data storage system as claimed in claim 24, wherein the secondary data storage subsystem is responsive to backup media remote control commands for mounting and unmounting specified tapes in a read/write station in the tape library unit, and for reading and writing to the tapes mounted in the read/write station.

28. The data storage system as claimed in claim 24, wherein the secondary data storage subsystem is responsive to backup media remote control commands for status information about a read/write station including identification of a tape mounted in the read/write station, storage capacity of the tape, block size of blocks stored on the tape, a current block number, and an amount of data storage space remaining on the tape.

29. A machine readable program storage device containing a program executable by a storage controller of a data storage subsystem having primary data storage, the storage controller having at least one data port for receiving storage access requests from at least one host processor, the storage controller being linked to a tape library unit for transfer of backup data between the storage controller and the tape library unit;

wherein the program is executable by the storage controller for receiving from the host processors storage access requests and in response controlling access of the host processors to the primary data storage;

wherein the program is executable by the storage controller for receiving from the host processors backup media remote control requests, and sending to the tape library unit backup media remote control commands corresponding to the backup media remote control requests for execution of the backup media remote control commands by the tape library unit, and for returning acknowledgments of the backup media remote control commands from the tape library unit to the host processors; and

wherein the program is executable by the storage controller for receiving from the host processors backup requests for backup of specified data in the primary data storage, and in response for transmitting commands to the tape library unit for storing backup versions of the specified data in tape storage in the tape library unit without requiring the host processors to issue backup media remote control requests for storing the backup versions of the specified data in tape storage of the tape library unit.

30. The machine readable program storage device as claimed in claim 29, wherein the program is executable by the storage controller for the storage controller to receive from the host processors backup media remote control requests that include SCSI commands, and to pass the SCSI commands to the tape library unit for execution by the tape library unit.