How to handle inconsistencies between tape media contents and OCDS TTOC records

When DFSMShsm detects an inconsistency between the TTOC record and the content of the tape media, an ARC0378I message is issued during the DFSMShsm startup to notify the system programmer that the missing TTOC record data set entries need to be resolved.

To get a list of all the volumes whose TTOC records are missing data set entries:

1. Issue a LIST TAPETABLEOFCONTENTS command with the SELECT(FAILEDCREATE) parameter. Inconsistent TTOC records for a failing DFSMShsm host will not be listed until DFSMShsm is restarted in that z/OS® image because the records appear to still be in use.
2. Use the extended AUDIT MEDIACONTROLS function to reconstruct the missing TTOC data set entries for the indicated tape volume.

   If data checks occur or invalid file block identifiers are encountered during AUDIT MEDIACONTROLS processing, a RECYCLE FORCE command can be issued to recycle the known valid data set entries on a tape volume. A warning message (ARC0378I) is issued, and the recycled tape volume is not deleted.

   In general, you should not use the RECYCLE FORCE command to recycle a tape volume before using the AUDIT MEDIACONTROLS command to resolve the missing TTOC data set entries. If you do use it, you must immediately perform the following steps to avoid losing the valid data sets on the just-recycled tape volume:

   1. Issue a LIST DSN MCDS SELECT(VOLUME(volume serial number of recycled migration tape)) command, or a LIST DSN BCDS SELECT(VOLUME(volume serial number of recycled backup tape)) command to list the data set names of the data sets that DFSMShsm indicates still reside on the tape volume.
   2. Recall or recover the indicated data sets that do not have TTOC data set entries associated with valid data sets residing on the tape volume.
   3. Issue a DELVOL command for the recycled tape volume.

When an ML2 tape volume cannot be deleted because an ARC0260I message indicates that valid data may exist on a volume, it is because the OCDS TTOC record indicates that the volume may contain valid migration copies. This condition occurs when an inconsistency exists between the TTOC record and the content of the tape media. Inconsistencies are created whenever TTOC creation or TTOC invalidation information is lost because of a DFSMShsm cancel, a system failure due to a power outage, or an I/O error on the OCDS.

A TTOC creation inconsistency is present when the ARC0260I message is preceded by an ARC0378I message that relates to the same volume. TTOC creation inconsistencies are resolved by running the extended AUDIT MEDIACONTROLS function to reconstruct missing data set entries on the OCDS TTOC record that relates to the tape volume. After the extended AUDIT MEDIACONTROLS function is completed for the inconsistent tape volume, the normal generic RECYCLE function established by the installation will DELVOL the tape volume after all valid data is moved to another ML2 tape volume. If an immediate DELVOL of the tape volume is necessary, the single volume RECYCLE function will DELVOL the tape volume after all valid data is moved to another ML2 tape volume.

A TTOC invalidation inconsistency is present when the ARC0260I message is not preceded by an ARC0378I message that relates to the same volume. TTOC invalidation inconsistencies are resolved by the normal generic RECYCLE function established by the installation. If an immediate DELVOL of the tape volume is necessary, the single volume RECYCLE function can be used. Either way, the RECYCLE function will DELVOL the tape volume after all valid data is moved to another ML2 tape volume.