Re: backup options

"Howard J. Rogers" wrote:
>
> "tshen" <tshen01_at_hotmail.com> wrote in message
>
> > Is oracle 8.1.7 allows DBA to put DB back into standby mode after
> > bring it up?
>
> Nope, utterly 100% absolutely impossible. Activating the standby causes a
> resetlogs to be issued, therefore it can never again becoem the standby. You
> are supposed to fix your old primary and turn that into the new standby.
> Again, if you want the ability to flip-flop between primary and standby
> roles, you need 9i.

This isn't entirely true... you can, if you're *very* careful and fully understand the Oracle recovery concepts, flip-flop between production -> standby -> production ad infinitum in pre-9i releases (back to 7.3 I believe). The process is too complex to describe in detail here, but if you do a search on "Graceful Switchover and Switchback for Oracle Standby Databases" in Metalink you'll find a white paper, written by Lawrence To, that describes a fully supported method of doing this. The basic idea is that the standby database is a exact backup of your primary. If you shutdown your primary cleanly, move the primary's online redo logs and recreate the standby's controlfile to look just like the primary's, and apply all archives, you can "fake out" Oracle into thinking the whole database has moved to a new machine. You never issue an "activate standby database" command, you never issue an "open resetlogs" command, so you don't have to rebuild/recopy anything.

This paper effectively describes how to manually accomplish what 9i DG graceful switchover does for you automatically.

Regards,
Sean M Received on Fri Jun 21 2002 - 00:50:06 CDT