I am somehow planning to have replication on another physical server as I ahve 2 physical server at my disposalyou're still going to have a problem when this one single physical server breaks
Our setup is quite similar to this. Except we use hardware firewalls that forwards traffic to a CARP address. We have two HAProxy machines running with CARP (fail-over). HAProxy then balances to 4 web servers. You could set up something similar by running CARP and HAProxy on the host and use the jails for the webservers.Should I combine HAProxy to load balance both the web and DB cluster?
We have them separated because the database servers and webservers have different hardware requirements. The DB servers have fast SSDs and a lot of memory (we need them to be as fast as possible). The webservers run on regular spinning disks and have a reasonable amount of memory. Most of the websites run from memory so there's very little I/O.Should I install the databases on the same server as the web (combine) or keep them separated?
You can designate one of the webservers as "master" and sync the others from it. For websites an net/rsync usually suffices. I'm assuming the website code itself doesn't change that often so there's very little reason to keep this in sync every second. Syncing when the site's been updated (on the master for example) should be more than enough.Can you think of anything I could do to keep my wordpress plugin sync between webserver in a cluster?