Hi,
As per my posts a few days ago, we backup an Oracle database while its
on-line. We put it into hotbackup mode, perform a backup to tape, and
then take the database out of hotbackup mode.
It was my understanding that this type of backup would be recoverable
using archive logs. Is my understanding not correct?
I've been unable to test a recover because we don't have the resources
to do so (disk space). But I've been concerned about this very issue
for a while and have been trying to muster the resources to try a
recovery.
We have another Oracle database that we backup by putting it in
hotbackup mode, then syncing BCV volumes, splitting the volumes, and
then taking the database out of hotbackup mode (the disks are on a EMC
Symmetrix). This method works well - we bring up the database on the
mirrored BCV volumes all the time. Of course this is slightly different
than going to tape, because on the BCV volumes all the files are a
snapshot from the same instance in time, while a tape backup isn't a
snapshot at one point in time because file X could have been backed up
at 12:00pm while file Y, on the same filesystem, could have been backed
up at 12:20pm, and so forth.
On Fri, 2004-03-12 at 08:43, Christopher T. Beers wrote:
> --On Friday, March 12, 2004 10:30 AM -0500 "Ciolek, Ken"
> <Ken.Ciolek AT AIG DOT COM> wrote:
> ...
> > We backup the entire box including all database files and the database is
> > not taken offline? Why is this a useless backup.
>
> The files are open by the database so since the database is writing to the
> file is changes while you back it up. The DB files are binary files are
> usually do not change size, but the contents change and need to be
> consistent in order to backup.
>
> If you choose not to run the modules you must either shutdown the database
> during the backup (look at savepnpc) or export the data into flat files
> nightly (or hourly if you need to recover data to a more closer point in
> time) and then back up the flat files.
>
> We use modules in someplaces and in others, we stop the database (of place
> it in hotbackup mode), we then copy the files by creating a snapshot of the
> filesystem (using fssnap with Solaris), start the DB back up, and then
> backup the snapshot location instead of the live DB files.
>
> --
> Christopher T. Beers
> UNIX Systems Engineer - Syracuse University
> 250 Machinery Hall Syracuse, NY 13244
> (315) 443-4103 Office (315) 443-1621 Fax
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