Re: Automated standby - swapping roles

Roman <rupa_at_firemail.de> wrote in message news:<pan.2004.07.09.16.59.16.582964_at_firemail.de>...
> Am Fri, 09 Jul 2004 07:29:27 -0700 schrieb B. Jones:
>
>
> > We have a script on the standby server running in cron that makes a
> > connection every minute to the primary database. If the connection
> > fails, it brings the standby server into production mode with ALTER
> > DATABASE ACTIVATE STANDBY DATABASE. According to Oracle/Lawrence To's
> > "Graceful Switchover and Switchback," that command will perform an
> > implicit open resetlogs, hence will not allow the procedures outlined
> > there.
>
> Additionally to "ALTER> DATABASE ACTIVATE STANDBY DATABASE" you have to
> shutdown
> startup
>
> On top of that usually one has to create the temorary TSP
>
> I can't think of any other procedure to bring up the standby.
> Wether it does "open resetlogs" ... don't konw. But I doubt it. Why should
> it?

Because when you activate the standby, it clears all buffers and resets the headers of the files. When you open it, it resets the redo log sequence. Oracle can't know whether you've lost anything before the activation, so it needs to start from a known point.

>
> > Additionally, as far as I could tell, there appeared to be downtime
> in
> > the procedures outlined in that strategy.
>
> It's certainly not an immidiate failover. Anyway, once the standby is up
> one has to tell all the clients where to connect to. So downtime is there
> anyway.

Not necessarily, but generally true practically.

>
> I would want to to this procedure by hand and not through scripts.

I would want to have people trained well enough to do it by hand and have them use scripts.

>
> > I was thinking that I could just export the database from server2 to
> > server1, build my standby controlfile from server2 and ftp to server1.
> > Will this work at all?
> > Ideas appreciated.
>
> Why export? It' s damn slow and obsolete. Will this work at all?
>
> In order to build up the standby DB I would recommend :
>
> Create the standby controlfile.
> Put the TSPs im "begin backup" and copy the datafiles to the target with
> scp, ftp, nc, rcp or what ever ... just not UPD based nfs.
>
> Even better use managed standy and let RMAN do the job.

8i has some nasty managed standby bugs that can affect the primary db.

>
> Greets Roman

jg

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