Hi,

I'm looking to setup an active passive LAMP cluster on RHEL 4. These servers will be virtualised on either VMware, or kvm very shortly.

The want is to be able to run any updates (app, d/b, patches) on one box only, and these changes would automatically replicated to the passive standby.

Assuming I could get all app code, (or even database as well) onto their own disk (block device), I've read that I could use http://www.drbd.org/

Maybe it's better to use native MySQL replication, Puppet for o/s patches, and just leave DRBD for app code update replication?

Any thoughts or feelings on this idea would be appreciated.

I'd probably only modify that slightly to: use a script to perform app updates on both hosts simultaneously, mysql replication for the db and puppet for the os patching.

Just a couple comments on your thread: the first thing that came to mind when I read this was mounting a cluster-aware filesystem for both virtual servers. But your approach (supplemented by kbp's suggestion) is probably wise.

If you go the DRBD route, I'd be very curious to read about your experiences after, say, a few months in production. Please consider posting them here (or on your LQ blog).