Re: Strategy question for 24X7, how to do cold backups?

"Luterin" <luterin_at_netscape.net> wrote in message news:9oqms9$8hl$1_at_atlas.net.metrotor.on.ca...
> > All web clients want a 24X7 solution. Immediately, hot backups
> > are needed. But, then, for a true 24X7, one must keep a copy of
> > all of the redo logs from day one and a recovery would take quite
> > awhile (Maybe I'm wrong here and the question is moot). On
> Not a big fan of hot backups... so, no comment here.
>
> > google, I am reading that one strategy is to configure a standby
> > database where the current database's redo logs are applied
> > against the standby. Then, if done correctly, a cold backup is
> > never needed? Even if it is, the standby can be used to produce
> > the cold backup?

Utter, utter rubbish. Sorry. But it's true. A standby database is absolutely, 100% no substitute for hot backups of your primary database.

> >
> As for a standby database, if the luxury of having duplicate (or more)
> resources exists, I feel it is an elegant solution for high availablity...
> and, there is no third-party software involved! Obviously, there are the
> additional administrative tasks one has to perform - I feel they are worth
> it.

You are probably in a minority of 1. Standby is fine, but it is not robust. Ever do a SQL Loader operation in direct path, nologging??? Most people do. Guess what? If it's not in the redo stream (and that's what nologging means) it's not replicated to the standby site. Feel like adding a new datafile to increase the size of a tablespace? Er... not replicated. Lose your primary current redo log... er, can never get that data into the standby database.

Standby is a lousy idea for avoiding the very simple and neat techniques available for doing hot backups on your primary site.

Don't confuse apples with oranges.

Regards
HJR
>
> To cold backup, take the standby database out of managed recovery mode,
shut
> it down, back it up, startup and perform manual recovery (using any
archive
> logs created by the primary database while the standby was down), and
place
> the standby database in managed recovery mode.
>
> Alternatively, standby database can be backed up while it is placed in
> read-only mode, thus avoiding the need to perform manual recovery.
>
> Also, while all this is going on, might as well set up hot backups of the
> primary database... for peace of mind, I suppose.
> -Lute.
>
>
Received on Fri Sep 28 2001 - 08:34:21 CDT