DATA SET AUTORECOVERY

• US 20130047032A1
• Filed: 08/19/2011
• Published: 02/21/2013
• Est. Priority Date: 08/19/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chauvet, Philip R., Reed, David C., Smith, Max D., Smith, Keith R.
• Granted Patent: US 9,037,901 B2
• Time in Patent Office: Days
• US Class Current: 714/15
• CPC Class Codes: G06F 11/00 Error detection; Error correction; Monitoring error detection, correction or monitoring in information storage based on relative movement between record carrier and transducer G11B20/18; monitoring, i.e. supervising the progress of recording or reproducing G11B27/36; in static stores G11C29/00
• CPC Class Codes: G06F 11/1469 Backup restoration techniques

Abstract

An approach to providing auto recovery of data sets in volumes. When an error condition results from an attempt to access an unintentionally deleted data set, an event is generated and sent to other systems with access to the volume in which the data set existed. The volume is also locked to prevent corruption during the recovery process. A system that has the unintentionally deleted data set open retrieves location information for the data set from control blocks in the system'"'"'s memory. This location information is used to build a new entry for the data set in the VTOC for the volume. When the data set is thus recovered, the data set is validated, the lock removed, and the data set is made available to the systems sharing the volume.

Claims

1. A computer program product stored on a computer-readable storage medium comprising instructions for:

receiving, on a first system, an error condition indicating that a virtual storage access method (VSAM) volume data set (VVDS) on a volume shared by the first system and one or more second systems is not found;

sending a request to one or more of the second systems in response to receiving the error condition, the request requesting VVDS location information from a second system that has the VVDS open; and

recovering the VVDS using the VVDS location information retrieved by the second system that has the VVDS open.

2. The computer program product of claim 1, further comprising:

locking the volume in response to receiving the error condition; and

maintaining the lock until one of;

recovering the VVDS; and

determining that the VVDS cannot be recovered.

3. The computer program product of claim 1, further comprising validating the VVDS following recovery of the VVDS.

4. The computer program product of claim 1, wherein the second system that has the VVDS open retrieves the VVDS location information from one or more control blocks created in volatile memory on the second system.

5. The computer program product of claim 1, wherein the VVDS location information is extent information that shows a beginning cylinder and track for the VVDS and an ending cylinder and track for the VVDS.

6. The computer program product of claim 1, wherein recovering the VVDS further comprises rebuilding an entry in the volume table of contents (VTOC) for the VVDS from the VVDS location information.

7. The computer program product of claim 1, further comprising the first system receiving a response comprising VVDS location information from the second system that has the VVDS open, and wherein the first system recovers the VVDS using the VVDS location information.

8. The computer program product of claim 1, wherein the second system that has the VVDS open recovers the VVDS using the VVDS location information, further comprising the second system sending a response notifying the first system that the VVDS is recovered.

9. The computer program product of claim 2, wherein the first system and the one or more second systems are organized as a sysplex.

10. A system comprising:

a virtual storage access method (VSAM) volume having one or more data sets;

a first system having access to the volume;

one or more second systems having access to the volume; and

a data set auto-recovery apparatus configured to;

receive an error condition from the first system indicating that a data set on the volume is not found;

send an request to the one or more second systems in response to receiving the error condition, the request requesting location information from a second system that has the data set open; and

recover the data set using the location information retrieved by the second system that has the data set open.

11. The system of claim 10, wherein the one or more second systems each comprise a listener for receiving the request.

12. The system of claim 10, each of the one or more second systems comprising volatile memory, and wherein each of the one or more second systems is configured to store the location information for open data sets in volatile memory.

13. The system of claim 10, wherein recovering the data set comprises rebuilding an entry in the volume table of contents (VTOC) for the data set from the location information.

14. The system of claim 10, wherein the second system that has the data set open sends the location information to the first system, and the first system recovers the data set.

15. The system of claim 10, wherein the second system that has the data set open recovers the data set.

16. A method comprising:

receiving, on a first system, an error condition indicating that a data set on a virtual storage access method (VSAM) volume shared by the first system and one or more second systems is not found;

sending an request to one or more of the second systems in response to receiving the error condition, the request requesting location information for the data set from a second system that has the data set open; and

recovering the data set using the location information retrieved by the second system that has the data set open.

17. The method of claim 16, further comprising locking the volume in response to receiving the error condition, and maintaining the lock until one of:

recovering the data set; and

determining that the data set cannot be recovered.

18. The method of claim 16, further comprising validating contents of the data set following recovery of the data set.

19. The method of claim 16, wherein recovering the data set further comprises rebuilding an entry in the volume table of contents (VTOC) for the data set from the location information.

20. The method of claim 16, wherein the data set is a volume data set (VVDS).