On Tue, 19 Apr 2005, David McDowell wrote:
> One in the same? Here's my idea. I'd like to use CentOS 4 if
> possible to do this. I would like to have my webserver mirrored on
> another machine so that if one goes down, the site continues to run.
> If I change a config on one machine, the config should change on the
> mirrored machine. Is this running a cluster or is this some other
> kind of setup? Basically I have some time at work to play. Any good
> resources for this kind of information? Basically I want 2 servers to
> be identical mirrors of one another so that if one of the 2 goes down,
> I'm still online. And, if I repair the broken one, it can resync
> itself so that the mirror of the 2 machines is identical again.
> Suggestions, links, etc?
The same, but not.
Take the following with a grain of salt, as I'm coming from the
standpoint of "CentOS is a rebuilt RHEL, RHEL has packages to do this,
why not pay up for it" despite knowing that's not gonna happen.
There are two types of clustering that I know of - high
availability and load balancing. HA gets you fault tolerance, LB gets
you greater throughput with a little bit of fault tolerance.
What you describe could be either - if you just need the data
replicated, and the actual httpd.conf won't change, LB would be easier.
set up a "shared" repo for the data, point both web servers at it for a
DocumentRoot, of off you go. If the httpd.conf will change, LB is still
possible, but more of a PITA, and then HA becomes easier.
Either way, doing it "right" involves a lot of extra stuff that
you probably won't be able to convince your boss to pony up for - like
true shared storage, multiple machines, etc.
Are you wanting to have tolerance between remove sites, or
between slots in a rack?
--
John Berninger
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