TCDB procedure for retrieving data from a disabled IBM automated tape library

There may be a time when you might experience a problem that could disable your IBM automated tape library. The following procedure provides instructions for retrieving data from an IBM automated tape library after a serious library manager failure occurs with the PC controller. By following this procedure, you can allocate your library volumes to stand-alone devices to retrieve your data after a few modifications to the TCDB and possibly the job stream. This procedure is only a short-term solution and should only be used if there is an immediate need for the data in the disabled IBM automated tape library.

Altering private tape configuration database records

Alter the TCDB for each private volume serial number from the disabled library that you plan to use. Use IDCAMS or a utility from your tape management system that invokes the IDCAMS facility. The LOCATION field in the TCDB must be altered from LIBRARY to SHELF. When altering the LOCATION field, IDCAMS also modifies the LIBRARYNAME field to SHELF. This field value change allows the private volume serial numbers to be used outside the library for non-SMS-managed requests. After the library manager is back online, and the volumes are returned to their home cells, the LOCATION and LIBRARYNAME fields in the TCDB must be altered. The LOCATION field must be altered back to LIBRARY and the LIBRARYNAME field must be altered to reflect the library name where the volumes reside.

The following are examples for the JCL for IDCAMS:

//ALTERVOL JOB 'NAME',MSGCLASS=H,MSGLEVEL=(1,1),CLASS=A
//**********************************
//*ALTER THE LOCATION FIELD TO SHELF FOR OAM100
//**********************************
//ALTER  EXEC PGM=IDCAMS
//SYSPRINT DD  SYSOUT=*
//SYSIN DD *
  ALTER VOAM100-
  VOLUMEENTRY-
  LOCATION(SHELF)
/*
//

//ALTERVOL JOB 'NAME',MSGCLASS=H,MSGLEVEL=(1,1),CLASS=A
//**********************************
//*ALTER THE LOCATION FIELD TO LIBRARY AND THE
//*LIBRARYNAME FIELD TO ATLF4007 FOR OAM100
//**********************************
//ALTER EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=*
//SYSIN DD *
  ALTER VOAM100-
     VOLUMEENTRY-
     LOCATION(LIBRARY)-
     LIBRARYNAME(ATLF4007)
/*
//

Changing from SMS-managed to non-SMS-managed requests

JCL jobs and applications that refer to scratch requests or to altered shelf-resident private volumes using DISP=NEW can be changed from SMS-managed to non-SMS-managed requests in one of two ways:

Modify the JCL or application associated PARMLIB member so that the requests are treated as non-SMS-managed requests.
Activate a new SCDS that treats the existing JCL and applications with no modifications as non-SMS-managed requests.

By changing to a non-SMS-managed request in the ACS routine, MVS allocation selects a non-SMS-managed device during the allocation process. Examine the constructs and the criteria used in the ACS routines to determine what requests need to be changed to non-SMS-managed.

Note: If storage groups selected from the ACS routine span multiple libraries, scratch allocations are automatically directed to the other libraries.

Changing the use attribute of scratch volumes

If you are using scratch volumes from the disabled library, then after the disabled library is back online either:

Use ISMF to alter the use attribute and the storage group, or
Code a CBRXLCS CUA invocation to change the use attribute from S to P and the appropriate storage group from *SCRTCH*

Either of these procedures must be done before any scratch requests are submitted. If one of them is not performed, then previously written data may be overwritten on the next scratch request to that library since the scratch volumes used still exist in a scratch category in the library manager inventory.

If you are using scratch volumes outside the disabled library, then after the disabled library is back online, enter those newly written volumes into the library and assign a use attribute of P and a storage group to preserve the data written on the volumes.

JCL jobs and applications that are referencing existing data on the altered private volumes with DISP=OLD or DISP=MOD may not require any changes. In this case, the ACS routines are not invoked and a device gets allocated based solely on the specified UNIT parameter indicated in the JCL or associated with the application program.

Note: If you have OAM Object Tape support and have altered the SETOAM parameters in the CBROAMxx PARMLIB member, you must restart the OAM address space in order for these changes to take effect.

Using the sample exit for volume not in library (CBRUXVNL)

After submitting the jobs and applications for the altered private volume serial numbers, the operator replies to a message from the CBRUXVNL exit. The operator either replies CONT to continue the request to a stand-alone device, or DISABLE to deactivate the volume not in library exit for future replies. By disabling the CBRUXVNL exit, the requests for the altered volume serial numbers are allocated to stand-alone devices, but for SMS-managed requests for volumes that reside on the shelf, the jobs fail. The CBRUXVNL exit can be re-enabled by using the OAM LIBRARY RESET,CBRUXVNL command.

Library manager database volume list

It is important to maintain a volume list that has the current home cell locations for your ATLDS library volumes. This volume list can be obtained from the library manager console by selecting DATABASE from the main menu pull-down window and then selecting a function called LIST DATABASE VOLUMES. This function generates a volume list that has the current home cell locations. This list can be saved on a diskette and referenced or printed with any remote PC ASCII editor. If you configured your Home Cell Mode to FLOAT, this operation will have to be run more often than if this mode was configured to FIXED. Floating home cells can change after volumes are demounted from the library devices. Maintaining these cell locations prevents the operator from manually searching for volumes in the disabled library.

Returning the library manager to an operational status

After the tape library is returned to an operational state, restore your modified JCL, PARMLIB members, and the TCDB records to their original values. Use the SMS library VARY command to vary the tape library online and then reactivate the original SCDS. After OAM has restarted, run an OAM library audit command to ensure that the volumes are returned to their correct home cell locations before allocating to that library.