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Can Oracle RMAN archive backups be applied to a Split Mirror DB Clone?

Alzhy
Honored Contributor

Can Oracle RMAN archive backups be applied to a Split Mirror DB Clone?

Am not really a DBA but we have been using Split Mirror Approaches to backing up VLDB Oracle Databases as well as clone databases.

Our DBAs often would ask us to restore filesystem based backups of oracle archive logs to bing up the cloned database on top of the HW based Split mirror.

My question is -- can't the DBAs just simply peruse of their RMAN archive backups to bring up the cloned database instead of asking us to restore from filesystem backups?

TIA.

Hakuna Matata.
4 REPLIES
Steven E. Protter
Exalted Contributor

Re: Can Oracle RMAN archive backups be applied to a Split Mirror DB Clone?

Shalom,

It depends on whether the archive log files are being backed up.

A db restoration is restore the database from rman or other source and then apply archive logs generated since the last cold backup.

Archive log files are large, sequential, and many shops don't back them up or move them regularly to avoid running out of disk space.

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TwoProc
Honored Contributor

Re: Can Oracle RMAN archive backups be applied to a Split Mirror DB Clone?

If you backup the archive logs via RMAN, then they exist in the RMAN catalog as items for RMAN's use, which does not include the "old way" or cloning, then restoring, then applying archive logs using "alter system recover database until cancel" method(or something similar in syntax). Instead that RMAN system would prefer you use one of the RMAN recovery methods (the one I mentioned above is NOT an RMAN recovery).

So, the trick would be for your DBAs to extract the archive logs from the RMAN catalog, instead of just using a regular file recovery from the sys admins...

this is the idea:

RMAN> run {
2> ALLOCATE CHANNEL c1 DEVICE TYPE DISK;
3> restore archivelog sequence XXXXX;
}

Here is a really nice link that explains it all very well, and it would allow your DBAs to recover archive logs into FILE form back onto disk from RMAN.

http://www.schemathings.com/?p=16
We are the people our parents warned us about --Jimmy Buffett
Alzhy
Honored Contributor

Re: Can Oracle RMAN archive backups be applied to a Split Mirror DB Clone?

Thanks TP..

It turns out it's a skills set issue.

Some of our DBAs simply do not have that much RMAN skillz.

I brought in HP Business Copy Sol'n for our VLDB backups coz I was pretty sure such solutions along with RMAN are the only platinum solutions for VLDB backups.

Our venerable DBAs however insist that RMAN to tapes is the uber best way and I had that impression it was not possible for a split mirror backup of an Oracle DB to be brought live/current with RMAN archive log backups.


Thanks also for the tip on how to make RMAN archive logs restored "file-like".

Hakuna Matata.
TwoProc
Honored Contributor

Re: Can Oracle RMAN archive backups be applied to a Split Mirror DB Clone?

FWIW - as for me, I'd go with Bus Copy over tape any day.

Re: source split mirror not split mirror, etc. It doesn't much matter, you can always recover the database into a new database name, with all new and different data paths, or new aliases for data paths. Lots and lots of options there.

My guess is that they like using RMAN from tape b/c of it's simplicity (once it's set up), and it is a valid point.
We are the people our parents warned us about --Jimmy Buffett