Method and system for emulating tape libraries

• US 20040111251A1
• Filed: 12/09/2002
• Published: 06/10/2004
• Est. Priority Date: 12/09/2002
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Alacritus, Inc.
• Inventors: Chang, Yafen Peggy, Johnston, Craig Anthony, Trimmer, Don Alvin, Stager, Roger Keith, Blaser, Rico, Cohen, Gavin David
• Granted Patent: US 8,024,172 B2
• Time in Patent Office: Days
• US Class Current: 703/26
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0686 Libraries, e.g. tape libraries, jukebox

Abstract

A method and system for emulating tape library commands is disclosed. Tape library commands implemented in response to commands received from a data protection application are emulated in a disk based storage medium so that existing data protection applications may be used to copy data to and from the disk based storage medium.

Claims

1. A method for emulating tape library commands so that data may be copied between a data protection application and a disk based storage medium, the method comprising:

a) receiving at least one command from a data protection application; and

b) emulating appropriate commands of a physical tape library in response to the data protection application command.

2. A method as in claim 1 wherein the step of emulating appropriate commands of a physical tape library in response to the data protection application command further comprises:

a) performing said commands virtually; and

b) sending an acknowledgement signal indicating that the data protection application command was performed successfully.

3. A method as in claim 2 wherein the step of performing said commands virtually further comprises:

a) recording state changes in the disk based storage medium resulting from instructions contained in the data protection application command that relate to moving components of a physical tape library; and

b) copying data to a location within the disk based storage medium, the location corresponding to a location in a physical tape library indicated in the data protection application command.

4. A method as in claim 2 wherein the step of performing said commands virtually further comprises:

a) recording state changes in the disk based storage medium resulting from instructions contained in the data protection application command that relate to moving components of a physical tape library; and

b) sending, along with the acknowledgement signal, data from the disk based storage medium to the data protection application, the data being sent from a location in the disk based storage medium corresponding to a physical tape location indicated in the data protection application command.

5. A method as in claim 1 wherein the step of emulating appropriate commands of a physical tape library in response to the data protection application command further comprises:

a) making a first determination of whether the data protection application command contains instructions related to moving components of a physical tape library;

b) recording state changes within the disk based storage medium caused by the instructions where the first determination is positive;

c) making a second determination of whether the data protection application command contains data and information indicating where in a physical tape library the data should be copied;

d) copying data to a location in the disk based storage medium, the location corresponding to a physical tape location indicated in the data protection application command; and

e) sending an acknowledgement signal indicating that the data protection application command was performed successfully.

6. A method as in claim 1 wherein the disk based storage medium is a virtual tape library.

7. A method as in claim 6 wherein the virtual tape library comprises a emulation module.

8. A method for emulating tape library commands so that data may be copied between a data protection application and a disk based storage medium, the method comprising:

a) receiving at least one command from a data protection application;

b) translating the at least one command;

c) recording state changes in the disk based storage medium resulting from instructions contained in the data protection application command that relate to moving components of a physical tape library;

d) copying data to a location in the disk based storage medium, the location corresponding to a location in a physical tape library indicated in the data protection application command; and

e) sending an acknowledgement signal indicating that the data protection application command was performed successfully.

9. A method as in claim 8 further comprising the step of:

a) sending, along with the acknowledgement signal, data from the disk based storage medium to the data protection application, the data being sent from a location in the disk based storage medium corresponding to a physical tape location indicated in the data protection application command.

10. A method as in claim 8 wherein the disk based storage medium is a virtual tape library.

11. A method as in claim 10 wherein the virtual tape library comprises a emulation module.

12. A system for emulating tape library commands so that data may be copied between a data protection application and a disk based storage medium, the system comprising:

a) a data protection application for backing up data to a physical tape library; and

b) a disk based storage medium comprising;

an emulation module for emulating appropriate commands of a physical tape library in response to at least one command received from the data protection application; and

a predetermined amount of disk storage space virtually corresponding to a physical tape library.

13. A system as in claim 12 wherein the emulation module is adapted to:

a) receive at least one command from a data protection application;

b) translate the at least one command;

c) record state changes in the disk based storage medium resulting from instructions contained in the data protection application command that relate to moving components of a physical tape library;

d) copy data to a location in the disk based storage medium, the location corresponding to a location in a physical tape library indicated in the data protection application command; and

e) send an acknowledgement signal indicating that the data protection application command was performed successfully.

14. A system as in claim 12 wherein data may be copied to a particular address in the disk based storage medium corresponding to a particular location on a particular physical tape in the physical library to which the disk storage space corresponds.

15. A system as in claim 12 wherein data may be retrieved by the data protection application from a particular address in the disk based storage medium corresponding to a particular location on a particular physical tape in the physical library to which the disk storage space corresponds.

16. A system as in claim 12 wherein the emulation module is adapted to emulate appropriate commands of multiple physical tape libraries.

17. A system as in claim 16 wherein the multiple tape libraries each correspond to a predetermined user where each predetermined user is limited to accessing their corresponding tape library.

18. A system as in claim 16 wherein the emulation module is a plurality of emulation modules.

19. A system as in claim 18 wherein the plurality of emulation modules each correspond to a predetermined user.

20. A system as in claim 16 wherein the multiple physical tape libraries each comprise different geometries.

21. A system as in claim 16 wherein at least one of the multiple physical tape libraries comprises an independently created predetermined geometry.

22. A system as in claim 12 wherein the appropriate commands emulated by the emulation module are commands necessary for supporting a particular data protection application.

23. A system as in claim 22 wherein the particular data protection application is said data protection application for backing up data to a physical tape library.

24. A system as in claim 12 wherein the emulation module is configured to perform logical unit number mapping.