Re: shutdown immediate or abort for cold-backup?

On Sat, 18 Aug 2001 11:39:19 GMT, lfc_at_zoom.co.uk (Leonard F Clark) wrote:

>I'm reluctant to get involved in what looks like becoming a minor
>flame war but I hope my comments may add value.
>
>I thought it was standard practice (and is certainly advice from

>Oracle) to do the following for batch shutdowns:
I find it hard to belive that Oracle would ever advice to use a shutdown abort in connection with a backup. Shutdown abort should only be used in emergency situations. Please tell *where* Oracle adviced it.

>
>1. Shutdown abort
>2. Startup normal (probably best in restricted mode)
>3. Shutdown normal
>
>Discussion:
>
>a) Although I have always been warned clear of shutdown aborts, I have
>never had any subsequent problems. In fact, if you think about it, a
>shutdown abort is no different from a shutdown immediate except that
>the rollback of active processes occurs on recovery (at startup)
>rather than as part of the shutdown process.

Not true.
 Shutting down abort leaves the database files in a more or less unsyncronized state. The volume of the mess depends on the actual state of the database when it was shutdown abort.

>
>b) by doing the three-step approach, the backup is taken after a
>normal shutdown and, therefore, should give clean results. If a
>problem *were* to result from the abort, by building enough checks
>into the script (return code and check for ORA- errors), you can abort
>the backup and raise warnings immediately.
>

You forget one problem : A shutdown abort is quick, but the recovery afterwards on startup may take a unpredictible *long* time..

You probably want to shutdown abort to avoid the risc of "shutdown immediate" taking a *long time*. But the time you win by "shutdown abort", is lost in the recovery of the database on startup.

In short : Don't use "shutdown abort" in connection with backup - ever.

>c) the one clear broblem in backing up an aborted shutdown is that, if
>you ever need to recover the database, you will always have to recover
>from the abort (which you have captured on tape). By clearing the
>recovery on step 2, you have a nice clean shutdown to recover from.
>
>Len
>
>>
Received on Sat Aug 18 2001 - 09:04:37 CDT