Apparatus, system, and method for optimizing recall of logical volumes in a virtual tape server

• US 7,757,052 B2
• Filed: 01/05/2005
• Issued: 07/13/2010
• Est. Priority Date: 01/05/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bello, Keith Anthony, Kishi, Gregory Tad, Friauf, Cheryl Marie, Norman, Mark Allan
• Primary Examiner(s): Kim; Matt
• Assistant Examiner(s): Birkhimer; Christopher D
• Application Number:
  US11/029,322
• Publication Number:
  US 20060149898A1
• Time in Patent Office: 2,015 Days
• Field of Search: 711/154
• US Class Current: 711/154
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0686 Libraries, e.g. tape libraries, jukebox

Abstract

An apparatus, system, and method are disclosed for recalling a logical volume from a mountable media for use in a virtual tape server. The apparatus includes a receiving module, a queuing module, and an optimizer module. The receiving module receives recall requests for logical volumes stored in a mountable media such as a tape cartridge. The queuing module places the requests in a queue to be processed in turn. The optimizer module reorders the queue based on one or more optimization rules in order to process the recall requests more efficiently.

Claims

1. An apparatus for recalling logical volumes, the apparatus comprising:

a receiving module comprising executable code stored on a storage device, executed by a processor, and configured to receive at least one recall request, each recall request being directed to a logical volume stored in a mountable media;

a queuing module comprising executable code stored on the storage device, executed by the processor, and configured to place each recall request in a queue for processing; and

an optimizer module comprising executable code stored on the storage device, executed by the processor, and configured to reorder the queue in accordance with at least one optimization rule, wherein the at least one optimization rule comprises grouping at least two recall requests sequentially in the queue, each of the at least two recall requests corresponding to a logical volume residing on a single mountable media and processing a first recall request based upon a status of a second recall request such that the first recall request is processed after the second recall request if the second recall request is previously displaced by reordering.

2. The apparatus of claim 1, wherein the at least two recall requests corresponding to a particular mountable media are grouped in queue according to a physical location of at least two recall requests on the mountable media.

3. The apparatus of claim 1, wherein grouping the at least two recall requests in queue comprises comparing one of the at least two recall requests corresponding to a logical volume located on a first mountable media, to a recall request corresponding to a logical volume residing on second mountable media.

4. The apparatus of claim 1, wherein the optimization rule comprises grouping at most nine hundred and one recall requests sequentially in queue, each of the at most nine hundred and one recall requests corresponding to a logical volume residing on a single mountable media.

5. The apparatus of claim 1, wherein at least one optimization rule is determined by a mathematical algorithm.

6. The apparatus of claim 5, wherein the mathematical algorithm is linear.

7. The apparatus of claim 5, wherein the mathematical algorithm is nonlinear.

8. An apparatus for recalling logical volumes, the apparatus comprising:

a receiving module comprising executable code stored on a storage device, executed by a processor, and configured to receive a plurality of recall requests, each recall request being directed to a logical volume stored in a mountable media;

a queuing module comprising executable code stored on the storage device, executed by the processor, and configured to place each recall request in a queue for processing; and

an optimizer module comprising executable code stored on the storage device, executed by the processor, and configured to reorder a first recall request in the queue based upon a status of a second recall request such that the first recall request is processed after the second recall request if the second recall request is previously displaced by reordering.

9. The apparatus of claim 8, wherein the optimizer module groups the first recall request with the second recall request when both requests are for logical volumes residing on the same mountable media.

10. The apparatus of claim 8, wherein the optimizer module is configured to process a first recall request before a second recall request when the first recall request has waited for a minimum wait threshold.

11. A system to recall logical volumes, the system comprising:

at least one drive unit configured to receive a mountable media containing at least one logical volume;

a tape library operably connected to the drive unit for providing a mountable media to the drive unit;

a cache configured to store a logical volume received from the mountable media; and

a memory containing modules for execution on a processor, the modules comprising;

a receiving module configured to receive a plurality of recall requests, each recall request being directed to a logical volume stored on the mountable media;

a queuing module configured to place each recall request in a queue for processing; and

an optimizer module configured to reorder the queue in accordance with at least one optimization rule, wherein the at least one optimization rule comprises grouping at least two recall requests sequentially in the queue, each of the at least two recall requests corresponding to a logical volume residing on a single mountable media and processing a first recall request based upon a status of a second recall request such that the first recall request is processed after the second recall request if the second recall request is previously displaced by reordering.

12. A program of machine-readable instructions stored on a storage device and executable by a digital processing apparatus to perform an operation to recall logical volumes from mountable media, the operation comprising:

receiving a plurality of recall requests, each recall request being directed to a logical volume stored in a mountable media;

placing each recall request in a queue for processing; and

reordering the queue in accordance with at least one optimization rule, wherein the at least one optimization rule comprises grouping at least two recall requests sequentially in the queue, each of the at least two recall requests corresponding to a logical volume residing on a single mountable media and processing a first recall request based upon a status of a second recall request such that the first recall request is processed after the second recall request if the second recall request is previously displaced by reordering.

13. The program of machine-readable instructions of claim 12, wherein the instructions further comprise grouping the at least two recall requests corresponding to a particular mountable media according to a physical location of the at least two recall requests on the mountable media.

14. The program of machine-readable instructions of claim 12, wherein the instructions further comprise grouping the at least two recall requests in the queue by comparing one of the at least two recall requests corresponding to a logical volume located on a first mountable media to a recall request corresponding to a logical volume residing on second mountable media.

15. A method for recalling logical volumes, the method comprising:

receiving a plurality of recall requests, each recall request being directed to a logical volume stored in a mountable media;

placing each recall request in a queue for processing; and

applying at least one optimization rule to reorder recall requests in queue for processing, wherein the at least one optimization rule comprises grouping at least two recall requests sequentially in the queue, each of the at least two recall requests corresponding to a logical volume residing on a single mountable media and processing a first recall request based upon a status of a second recall request such that the first recall request is processed after the second recall request if the second recall request is previously displaced by reordering.

16. An apparatus to recall logical volumes from a mountable media, the apparatus comprising:

means for receiving a plurality of recall requests, each recall request being directed to a logical volume stored in a mountable media;

means for placing each recall request in a queue for processing; and

means for reordering the queue in accordance with at least one optimization rule, wherein the at least one optimization rule comprises grouping at least two recall requests sequentially in the queue, each of the at least two recall requests corresponding to a logical volume residing on a single mountable media and processing a first recall request based upon a status of a second recall request such that the first recall request is processed after the second recall request if the second recall request is previously displaced by reordering.