RE: Backup questions (RMan and NetBackup)

From: Lawie, Duncan <duncan.lawie_at_credit-suisse.com>
Date: Wed, 2 Aug 2006 10:06:48 +0100
Message-ID: <07150B51CE30744CBBB58E696139708DFDDB25@elon11p32002.csfp.co.uk>

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Sarah Satterthwaite Sent: 31 July 2006 19:27

> RMan catalog versus just the control file (I haven't tried creating a catalog so
> far in my testing):

>	When is this useful?  My 10.2 environment consists of just one database (and

> soon a standby) plus a NetBackup server for that system only.
> Since only one database is involved, all the catalog would buy me is a longer
> history of backups than will fit in the control file. It does not seem worth the > trouble and I don't have a machine in that environment to put the catalog on. Am
> I missing something here?

Not missing much - although the catalog is very useful if you've lost your controlfile as well. So, without a catalog, you ought to make sure you are doing a binary backup of your controlfile and managing the location of that carefully.

>	I have multiple 8.1.7 databases to backup to a single NetBackup Server.  Is

> there an advantage to having a recovery catalog when multiple databases are
> involved? Does it make tracking things easier?

It is quite handy for tracking, in that you have a central location where you can run SQL queries to report on the state of backups.

> I want to backup the databases to disk and then to tape, leaving the latest disk
> copy around in case we need it. Is the best way to do this to:

> Backup the database to disk and then backup those backup sets to tape.

> Backup 2 copies, one copy going to tape and one to disk (I haven't tried
> doing this and am not sure it is even possible).

I would certainly recommend a backup to disk and then to tape - with the second backup managed by RMAN as well - e.g. with a backup backupset instruction. This means that the database is only being read once, and that the catalog knows that the backup has gone to tape.

> The NetBackup documentation mentions staging areas where the files on disk
> then get swept to tape periodically. Is this a path that is worth investigating?

If this is what I think it is, you are losing half the value of using RMAN for cataloging in the first place. i.e. if you use RMAN to back up to disk and then let operating system level backups copy these off to tape, then RMAN doesn't know where to find them on tape. However, if you don't want to spend the money on the Oracle Netbackup Agent, then this is the only way of getting to tape.

> Are backup sets or image copies preferred? I like the idea of skipping all those
> unused blocks, but the manual seems to imply that image copies are preferred as
> they have less overhead.

Image copies are space-heavy and of limited value once they get to tape anyway.

> For control file autobackups. are their problems with setting the format to
> something besides the default?

None that I'm aware of.

A bit of a caveat - it's a long time since I looked at RMAN on 8i, so my perspective is rather skewed to the way it works with 10.2.

Cheers,
Duncan.

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Received on Wed Aug 02 2006 - 04:06:48 CDT