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Trying to figure out restore behavior of a multiplexed backup


I have a restore running of a Oracle/SAP database using RMAN. 

The backup policy specifies a multiplex setting of 2.  RMAN submits 4 jobs (specfied somewhere in RMAN).  So four jobs run and write to two tapes - in this case (lets say) tape abc123 and xyz345.

There is no data from other backup policies on these tapes; the pool is unique to this policy.  So  I dont need to be concerned about the restore having to skip over 'irelevant' data.


When the restore jobs are being submitted *sometimes* I see that one job appears to be idle.  In the snapshot below the first two jobs show that tape abc123 are mounted for that job.  And the second two jobs have tape xyz345 mounted.  The last two jobs are both cooking along fine - reading the data on tape xyz345.

But the first job of the first two jobs just seems to be idle (no KB/second).  I dont understand why this job would be behaving differently.  The tape it needs is mounted; why isn't it restoring any data?


LEF restore.png


Level 4
Employee Accredited Certified

As you mention that this only happens intermittently, you may need just a slightly higher MPX_RESTORE_DELAY.  There is a great explanation in this technote:

For more info on the setting (and how to set through the GUI) see:

I hope that helps!


L - Thanks - I have up'ed this parameter and will see what happens next time we do a multiplexed restore.