During the middle of an online DB2 database backup, there is a restore job initiated which is asking for the same tape as the backup job which is causing the backup to "hang".

Starting in DB2 version 9.5, the "online" database backup by default includes the archive logs created since the last backup.  

If the database and archive log backups are going to a tape medium and share the same volume pool and retention periods, they may be written to the same tape.

This can cause issues during a DB2 online database backup, since it will want to include any archive logs that were generated since the last backup.  This will cause the backup job to pause until a restore job has completed for any archive logs that are no longer available.  If the logs were previously backed up to the same tape that the database backup is using, a stale mate or hang condition will occur.

The recommended solution is to implement one of the following:

1.  Configure the DB2 archive log backups to use a separate tape volume pool or retention period.  This will ensure the database and archive backups are directed to different tapes so the restore will not deadlock.

2.  Configure the DB2 archive log backups to go to a disk based storage unit rather than tape.

3.  You can use the option "exclude logs" from the DB2 online backup command, so that just a database backup would be taken and not include the archive logs.

See 000037053 in the Related Articles section for the details about the resulting error condition.