Re: Warm standby failover mechanism

On Wed, Feb 25, 2009 at 09:26:26AM +0000, Thom Brown wrote:

> We've set up a primary server in archive mode to continuously archive to an
> NFS mount, and the standby server to continuously recovery from that
> directory (although I'm not sure that's actually working... I've probably
> overlooked something). The problem we face is working out how to tell the
> standby server that it is the primary. Yes this can be done with a trigger
> file in /tmp, but how would that automatically appear there?

Think backwards: How would it automatically *dis*appear from
there. Have the secondary create it and check for existance
at regular intervals. Have the primary delete it at slightly
shorter intervals.

When the secondary finds it again after the check interval
the primary didn't delete it. Wait some more for good
measure and/or try to ping the primary some other way...

Just my 2 cents,
Karsten
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