How to Prepare and Recover CA Vtape › Virtual Volume Recovery › Recall from a Virtual Duplex Backstore Tape

Recall from a Virtual Duplex Backstore Tape

The Group Definitions control whether Virtual Volumes are written to primary and duplex Backstore tapes. If a duplex Backstore tape was created, problems with a primary tape are automatically addressed by CA Vtape by recognizing the error condition and mounting the duplex tape instead. The Group attributes that control automatic recovery are:

• RecallAttemptsThreshold
• OffsiteBackstoreCopy

During CA Vtape Recall processing, the primary Virtual Volume data set name is located first. If the primary is not found, the duplex Virtual Volume data set is then located. The locate order can be reversed by using the SVTn SET RECALL=Duplex console command to tell CA Vtape to locate the duplex version first. This command is typically used at a disaster recovery site when only the duplex Backstore tapes are available.

You can force the use of a duplex copy by uncataloging the primary after verifying that the duplex exists. If you are going to uncatalog Backstore tape entries, document them first so that they can be recataloged with IDCAMS DEFINE NONVSAM commands later. Recataloging is required before running the Recycle utility to rebuild a lost or broken Backstore tape from its copy.

You can determine whether a duplex exists by using ISPF 3.4 to look-up the standard Backstore data set name of PREFIX.VVE.Vvolser, where volser is the virtual VOLSER in question, will provide the required information.

For example, using the default CA Vtape prefix, Virtual Volume 899186 might display the following information:

CAVTAPE1.VVE.V899186.DUPLEX 
CAVTAPE1.VVE.V899186.PRIMARY 

Having verified the existence of the duplex copy of 899186, the primary copy can be uncataloged with the ISPF panels and subsequent Recalls of 899186 will call for the duplex tape.

Caution: RECYCLE PHYSICAL REPAIR reads the ICF catalog to determine which Virtual Volumes are currently on the bad primary Backstore tape so their corresponding duplex copies can be read to create a new primary tape. Using the example above, if the uncataloged primary entry for 899186 is not recataloged before Recycle is executed, the new primary Backstore tape will be missing 899186.