Re: Getting a consistent copy

From: John Hurley <johnbhurley_at_sbcglobal.net>
Date: Tue, 21 Jul 2009 06:55:23 -0700 (PDT)
Message-ID: <a770ab38-6c8d-4898-aeb8-07551fa13159_at_y19g2000yqy.googlegroups.com>



On Jul 20, 8:19 pm, Pat <pat.ca..._at_service-now.com> wrote:

snip

> > > One thing we're considering trying here to achieve the same thing
> > > though is to use SAN snapshotting, something like this:
>
> > > 1) Leave the source running
> > > 2) SNAP /u01 on the san
> > > 3) Mount the SNAP on a different database server in read/write mode
> > > 4) Restart Oracle over there
> > > 5) Let it go through a recovery (since we did just crash it)
> > > 6) Run a data pump export out of there.
>
> > > Is anybody doing something like this? Does anybody know of any
> > > subtleties that I should be aware of? In theory the above should work
> > > fine, but as one of my colleagues is fond of pointing out, in theory
> > > you shouldn't need practise.
>
> > Yup doing this all the time ... we are using EMC on Clariions ... and
> > using a clone ( full copy ) not a snap ... but same basic thing.
>
> > Yes there was at least poster noting that this technique failed for
> > them on extremely high volume transactions rate systems.  I haven't
> > seen it fail on any of the systems I have worked on.
>
> > We use this technique to refresh a test and/or dev database with fresh
> > data.  Usually we also get a local clone of the refreshed database so
> > that it can be restored multiple times to the same starting point
> > ( groundhog day ) in a testing loop.
>
> Thanks, that's exactly what I needed to hear.
>
> We're on netapp, not EMC, but same basic feature set for this sort of
> thing.
>
> Appreciate the feedback,

I guess I can add that this technique can also work well with ASM based diskgroups but you have to compromise so that the diskgroups support just one instance. In other words ... before the instance recovery ... mount to ASM the diskgroups necessary ... ASM will recover ( if needed ) first ... then the regular instance startup will do the database recovery. Received on Tue Jul 21 2009 - 08:55:23 CDT

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