Re: Multiple HDR secondaries...

Madison Pruet wrote: > I've heard from some folks a request for multiple secondaries within HDR. > > I'd like some idea as to what the business reasons for such a request and > what the expected behaviour would be of such a feature . The business reasons I see are: 1. Multiple servers from which reports can be run without impacting on the performance of the primary server. 2. The usual reason for a HDR switchover is because of a hardware failure. When this occurs a customer is left vunerable with just one working server. This would not be a problem if there was a second HDR secondary. As an aside we sometimes procure a third server to which we restore ontape backups. Provided the backup is recent enough this tertiary server can be synchronised with the primary server and become the HDR secondary if the usual secondary fails. 3. HDR is a little simpler to use and maintain than ER which is not available with Workgroup edition anyway. 4. Sell more Informix licences to shops using HDR at the moment? Expected behaviour: We don't use any auto-failover capabilities so I would leave others to suggest how this might work. I would expect that any secondary HDR server would be able to synchronise with the primary provided the secondary's current logical log is still on the primary server. I guess the "onmode -d primary" command could be altered so that it takes a list of space separated secondary servers and not just one. Perhaps there could be a new command to instruct the primary to start or stop synchronising with a secondary server as appropriate. I would like to see a feature (and this may already exist in IDS 10) whereby if you choose to changeover a HDR pair, it would not be necessary to perform a full archive on the primary and restore on the secondary in order to get HDR working again. I know there was an undocumented and unsupported way of doing this in 9.30 at least if not before.