High Availabilty Clustered Hosting with WHM

This functionality is not natively supported by cPanel/WHM so you proceed at your own risk.

Typically such setups have 2 cPanel/WHM servers and a separate appliance or server to handle directing traffic to the appropriate server.

You would need to mirror the contents of both servers. In a load-balancing environment, centralized storage may be the most practical method of keeping the files up to date on both servers. Many that do implement centralized storage use iSCSI rather than NAS since iSCSI has better handling of disk quotas.

You would also need to have the databases be identical on both servers. You may wish to investigate MySQL Clustering as a means to do this. You may find the following presentation from the 2008 cPanel Conference useful in understanding how you could do this in a cPanel/WHM environment:

http://twiki.cpanel.net/twiki/pub/AllDocumentation/TrainingResources/TrainingSlides08/RemoteMYSQLServer.pdf

Again, all of this is at your own risk. None of this is supported by us at this time. I'm just providing advice on possible ways to do this.

 

Cpanel does indeed have basic DNS clustering although it could be better but
there are some tricks to get around it's shortfalls. Anyway, I believe
cPanelDavidG was talking about the "mirroring" of the sites themselves not
being directly supported by Cpanel but those too are fairly simple to setup.
You just can't simply go into a single Cpanel menu to do it!

You will need to make a few modifications to the zone files for your domain
on both servers, setup DNS clustering, possibly adjust your settings for
the domain at your registrar, setup a link between your servers if you
are using MySQL or PgSQL, and update the HTTPD.CONF on each server
and restart all the related processes listed above.

It's actually not that difficult to setup but just isn't natively supported
by Cpanel itself yet although that would be a nice idea for a future release.
*HINT* *HINT*