Tape storage emulation for open systems environments

• US 20060123189A1
• Filed: 01/23/2006
• Published: 06/08/2006
• Est. Priority Date: 02/05/2003
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: Diligent Technologies Corporation (International Business Machines Corporation)
• Inventors: Akirav, Shay, Bitner, Haim, Drobchenko, Elena, Bash, Shira, Krikler, Samuel
• Granted Patent: US 7,853,764 B2
• Time in Patent Office: Days
• US Class Current: 711/111
• CPC Class Codes: G06F 11/1458 Management of the backup or restore process
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• 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 3/065 Replication mechanisms
• 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
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A Virtual Tape (VT) server residing on a network is connectible on its front end to a plurality of heterogeneous backup hosts, with different operating systems and/or backup applications, and on its back end to one or more disk storage devices in an open systems environment. The VT server responds to tape storage commands sent by the backup host as if it were the intended tape storage device and then emulates the desired tape storage activity on the one or more disk storage devices. In a described implementation, the host and server act as SCSI initiator and target and communicate over a Fibre Channel connection.

Claims

1. A method for storing backup data on a virtual tape (VT) server residing on a network and connectable to one or more disk storage devices and connectable to a plurality of backup hosts in an open systems environment, wherein the VT server receives tape storage commands, said tape storage commands including commands in tape device format, each tape storage command directed to a respective target tape storage device, the method comprising the VT server:

accepting the tape storage command and responding as if the VT server were the respective target tape storage device; and

emulating the respective target tape storage device by converting the received tape storage command to at least one disk storage command for implementing the received tape storage command with the one or more disk storage devices,

wherein the tape storage commands further include commands in robotics format and the step of emulating includes providing a model describing a tape library including robotics and tape drive devices, including the emulated target tape storage device, whereby the VT server emulates the tape drive devices and robotics.

2. The method of claim 1, wherein configuration and status information for one or more virtual tape storage devices corresponding to one or more target tape storage devices emulated by the target emulator is stored;

and

wherein the configuration and status information are updated as a function of the received tape storage commands.

3. The method of claim 1, wherein a backup application on a backup host stores status information of the target tape storage devices to which the backup application has directed tape storage commands, and said status information stored in the backup application corresponds to the status information stored in the VT server.

4. The method of claim 1, wherein the model includes tape objects and robot objects.

5. The method of claim 1, wherein emulation data is stored describing the emulated target tape storage devices.

6. The method of claim 5, wherein the emulation data has a data structure including one or more of the following fields:

configuration information, cartridge directory, and cartridge data.

7. The method of claim 5, wherein the emulation data has a data structure including one or more of the following fields:

configuration information, robot mailbox, bin mailbox, tape mailbox, import/export mailbox, and share mailbox.

8. The method of claim 7, wherein the emulation data has a data structure including one or more of the following fields:

configuration information, cartridge directory, and cartridge data.

9. A computer-implemented virtual tape storage system comprising:

a front end connectable to one or more heterogeneous hosts in an open systems environment and configured to accept tape storage commands from the one or more hosts, said tape storage commands including commands in tape device format, each tape storage command identifying a target tape storage device;

a target emulator, coupled to the front end, to receive the tape storage command and emulate, as a corresponding virtual tape storage device, the target tape storage device identified in the tape storage command;

a command converter, coupled to the target emulator, to receive the tape storage command and convert the tape storage command into one or more disk storage device commands as a function of the virtual tape storage device;

a back end, coupled to the command converter, to receive the one or more disk storage device commands and to forward the disk storage device commands to one or more disk storage devices coupled thereto,

wherein the tape storage commands further include commands in robotics formats, the virtual tape storage system further comprising a model describing a tape library including robotics and tape drive devices including the emulated target tape storage device, whereby the emulation of the target tape storage device comprises emulating the tape drive devices and robotics.

10. The system of claim 9, wherein the one or more disk storage devices comprise one or more of a disk drive and a disk array.

11. The system of claim 9, wherein at least one of the hosts has a backup application which issues the tape storage commands and serves as a single point of management and control for backup operations.

12. The system of claim 9, wherein configuration and status information for one or more virtual tape storage devices corresponding to one or more target tape storage devices emulated by the target emulator is stored;

and

wherein the configuration and status information are updated as a function of the received tape storage commands.

13. The system of claim 9, wherein the model includes tape objects and robot objects.

14. The system of claim 9, wherein the tape storage commands are Small Computer System Interface (SCSI) commands.

15. The system of claim 14, wherein the SCSI commands are adapted for Fibre Channel (FC) transmission.

16. The system of claim 9, wherein the target emulator identifies itself as either a SCSI stream device or a SCSI medium changer.

17. The system of claim 16, wherein the tape storage commands comprise SCSI tape storage commands addressed to tape storage devices with logical unit numbers (LUNs).

18. The system of claim 9, wherein a virtual tape (VT) server provides the target emulator and command converter, and wherein a disk library unit comprising said one or more disk storage devices is coupled to the VT server to receive the one or more disk storage commands.

19. The system of claim 18, wherein a backup application on a backup host stores status information of the target tape storage devices to which the backup application has directed tape storage commands, and said status information stored in the backup application corresponds to the status information stored in the VT server.

20. The system of claim 9, wherein emulation data is stored describing the emulated target tape storage devices.

21. The system of claim 20, wherein the emulation data has a data structure including one or more of the following fields:

configuration information, cartridge directory, and cartridge data.

22. The system of claim 20, wherein the emulation data has a data structure including one or more of the following fields:

configuration information, robot mailbox, bin mailbox, tape mailbox, import/export mailbox, and share mailbox.

23. The system of claim 22, wherein the emulation data has a data structure including one or more of the following fields:

configuration information, cartridge directory, and cartridge data.

24. A computer-readable medium containing computer-readable instructions enabling a computer to perform a method comprising:

accepting tape storage commands from heterogeneous hosts over channel network connections in a manner transparent to the hosts, said tape storage commands including commands in tape device format, each tape storage command identifying a target tape storage device; and

upon receipt of a tape storage command;

emulating, as a corresponding virtual tape storage device, the target tape storage device identified in the tape storage command by converting the tape storage command into one or more disk storage device commands as a function of the virtual tape storage device; and

forwarding the disk storage device commands to one or more disk storage devices,

wherein the tape storage commands further include commands in robotics formats, and wherein the step of emulating includes a model describing a tape library including robotics and tape drive devices, including the emulated target tape storage device, whereby emulation of the target tape storage device comprises emulating the tape drive devices and robotics.