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Is neccesary sincronized oracle database after fail backup?

Hi Guys,

I was doing some research but to be honest I can't find anything about this.

The DBA asked me if, after a failed oracle backup, it is necessary to run crosscheck or synchronize the database before the backup admin has to restart the job.

Does anyone have ideas?

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Re: Is neccesary sincronized oracle database after fail backup?

I have limited (read none) experience with Oracle.

I've never heard of the term "Oracle database synchronization", so I've not idea what your DBA might be implying with regards to that.

As for a crosscheck, then yes, I would have thought that a DBA would want to (but does not need to) perform a cross-check after a failed backup.  A "cross-check" is essentially about the Oracle database itself asking/querying/probing the MML (Media Manager Layer) (i.e. NetBackup) for a list of known (i.e. still retained) backups, so that Oracle can adjust its own view of what is still retained, so that Oracle can determine (if required) which elements of pre-existing data needs to be backed-up again, or new data that needs to be backed-up for the first time ever.  Essentially, the requirement as to whether to perform a cross-check is always down to how the DBA originally configured their backup jobs in the first place, and down to how those jobs continue to run day-to-day.  IMO, only an Oracle DBA can know whether they need to perform a cross check or not.  Normally a "backup" admin/engineer is not concerned about how or why or whether an Oracle cross-check needs to be performed or not... unless the DBA starts to run too many cross-check jobs.  (BTW: a cross-check job in Oracle speak is synonomous with a bplist in NetBackup speak) (and a bplist in turn causes a query via bpdbm).

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Re: Is neccesary sincronized oracle database after fail backup?

I would say no, corsscheck should however be performed before every retore operation to ensure Oracle and Netbackup agree on what backups exists.

If a backup fails, RMAN know the backup failed via the media manger layer, but RMAN doesn't know when a backup image expire in Netbackup. This is where the crosscheck operation comes into play

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Accepted Solution!

Re: Is neccesary sincronized oracle database after fail backup?

I have limited (read none) experience with Oracle.

I've never heard of the term "Oracle database synchronization", so I've not idea what your DBA might be implying with regards to that.

As for a crosscheck, then yes, I would have thought that a DBA would want to (but does not need to) perform a cross-check after a failed backup.  A "cross-check" is essentially about the Oracle database itself asking/querying/probing the MML (Media Manager Layer) (i.e. NetBackup) for a list of known (i.e. still retained) backups, so that Oracle can adjust its own view of what is still retained, so that Oracle can determine (if required) which elements of pre-existing data needs to be backed-up again, or new data that needs to be backed-up for the first time ever.  Essentially, the requirement as to whether to perform a cross-check is always down to how the DBA originally configured their backup jobs in the first place, and down to how those jobs continue to run day-to-day.  IMO, only an Oracle DBA can know whether they need to perform a cross check or not.  Normally a "backup" admin/engineer is not concerned about how or why or whether an Oracle cross-check needs to be performed or not... unless the DBA starts to run too many cross-check jobs.  (BTW: a cross-check job in Oracle speak is synonomous with a bplist in NetBackup speak) (and a bplist in turn causes a query via bpdbm).

View solution in original post

Highlighted
Accepted Solution!

Re: Is neccesary sincronized oracle database after fail backup?

I would say no, corsscheck should however be performed before every retore operation to ensure Oracle and Netbackup agree on what backups exists.

If a backup fails, RMAN know the backup failed via the media manger layer, but RMAN doesn't know when a backup image expire in Netbackup. This is where the crosscheck operation comes into play

View solution in original post

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Re: Is neccesary sincronized oracle database after fail backup?

Thank you, guys. Very helpful information.