Re: Fssnap and Oracle 9i

Roel Toledo wrote:

> Id' like to solicit opinions from other DBA's in this forum about
> Solaris 9's online backup utility fssnap and using it to backup an
> Oracle database server. Do the database instances need to be shut
> down first before issuing fssnap? In the event that fssnap backup is
> made while the database is up and running, can the backups be safely
> restored without a problem?

I don't know fssnap, so I could be wrong. But I do know Oracle's internal shenanigans that get stuffed by O/S backups done incorrectly, so I'll bet I'm not.

The instances would indeed need to be shutdown before taking your backup. The problem is simply a generic one: an operating system utility cannot know the significance of the first block in a data file's header. Nor can it understand that 16 512 byte blocks need to be copied in synchronism before you can say you've backed up one Oracle block. Only an Oracle-aware utility can do that (such as RMAN). Therefore, if the instances are still running, you risk fractured blocks and inappropriate data file headers.

Ana's suggestion to test it is not, in this case, sufficient, I would suggest. Because whether or not you actually suffer from fractured blocks or inappropriate data file headers is actually a matter of chance. You might test it, and it all works perfectly... but that was just good luck. When it comes to backup and recovery, you don't take chances. You adopt the strategy that you know will work 100% of the time.

In your specific case, go ask Sun (or whoever) whether fssnap is Oracle-aware, and if it isn't, then don't use it with running instances.

For Oracle, you should be using RMAN.

Regards
HJR Received on Fri Oct 08 2004 - 16:29:08 CDT