Re: Fssnap and Oracle 9i

"Howard J. Rogers" <hjr_at_dizwell.com> wrote in message news:<41705773$0$24889$afc38c87_at_news.optusnet.com.au>...
> Joel Garry wrote:
>
> > "Howard J. Rogers" <hjr_at_dizwell.com> wrote in message
> > news:<4167074d$0$23893$afc38c87_at_news.optusnet.com.au>...
> >> 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.
> >
> >
> http://sunsolve.sun.com/search/document.do?assetkey=1-9-49622-1&searchclause=fssnap
> >
> >>
> >> 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.
> >
> > Isn't that what hot backups are for?
>
> Joel: could you try to note what the actual topic of conversation here is,
> before joining in? The OP wrote, "I'd like to solicit opinions about
> fssnap".
>
> *My* comments are addressing his question.
>
> What are your comments doing?

Addressing apparent incorrectness in your comments that are addressing his question. Your answer didn't seem up to your usual standards, I got the idea you were under the weather or something. OK, maybe I'm stupid, perhaps you can explain in short sentences why an instance has to be shut down and hot backups don't work. I was saying they work, but they are operationally stupid for fssnap type use. If I'm wrong about when Oracle writes to files, that's fine too, please explain.

>
> Yes, we know that Oracle has a hot backup capability. But the question was
> actually, how good is fssnap.

So, if you don't know anything about fssnap, why were you saying anything at all?

Come on, Howard, this is a usenet group, where oftentimes bits and pieces of an answer can come from various sources. Thread drift can actually help. The OP appears unfamiliar with the way Oracle and OS utilities interact, and indeed you should look at subject line again. A strict limitation to fssnap would not be addressing the subject. Certainly the thread context extends the question to "I'd like to solicit opinions about" how OS utilities and Oracle interact.

jg

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