System Programmer Reference › User Exits › Restore Link (VMBEXIT4) User Exit

Restore Link (VMBEXIT4) User Exit

Use the restore link user exit, VMBEXIT4 to change the link mode on the CP LINK command issued when restoring data to minidisks. You can also use VMBEXIT4 to send messages to users and other service virtual machines to detach the target minidisk or perform other quiescing or setup processing required to prepare the target minidisk for the restore. This is similar to the function performed by the quiesce user exit, VMBEXIT2, during backup jobs.

There are three primary reasons to use this user exit:

• To link mult/write (MW) to specific database minidisks that cannot be detached or taken down for restores.

  Important! CMS and CA VM:Backup do not protect against loss of data on a minidisk when more than one user has write access to the minidisk. When multiple users write to the same minidisk, data can be permanently lost. Use the MW link mode with caution

• To select the link mode for all restores to particular minidisks and override the link mode selected by users through the Specify Restore Options screen.

  Users requesting a restore can select the link mode, either write or mult, to the target minidisk with the end-user Specify Restore Options screen. This is done for each restore. For instructions on using this screen, see the CA VM:Backup User Guide.

• To prepare the target minidisk for the restore. This can include any setup processing or quiescing of the minidisk needed before the restore proceeds. VMBEXIT4 can also send customized messages to users or service virtual machines to alert them to prepare for an upcoming restore.

CA VM:Backup automatically checks whether a VMBEXIT4 EXEC exists. If it does, CA VM:Backup passes control to VMBEXIT4 EXEC just before the link is established to the target minidisk specified in the restore job, including restore jobs submitted by and authorized client, such as CA VM:Archiver. The user exit can then change the link mode of the CP LINK command issued to link the minidisk to which the data will be restored.

Only one restore link user exit can exist. Because all restore jobs will call this user exit, make sure that VMBEXIT4 is coded to include cases for all minidisks that may be target minidisks for a restore job.

For audit purposes, CA VM:Backup issues message 364I if VMBEXIT4 changes the link mode.