live mirroring

[Peter Risdon]

On Mon, 2005-02-14 at 10:59 +0100, Gerard Meijer wrote:

> ----- Original Message ----- 
> From: "Peter Risdon" <peter at circlesquared.com>
> To: "Gerard Meijer" <gmeijer at palmweb.nl>
> Cc: <freebsd-questions at freebsd.org>
> Sent: Monday, February 14, 2005 10:49 AM
> Subject: Re: live mirroring
> 
> 
> > On Mon, 2005-02-14 at 10:22 +0100, Gerard Meijer wrote:
> >> Hi all,
> >>
> >> I have a question. I want to set-up a site on 3 identical FreeBSD 
> >> servers, using Round Robin to distribute the load.
> >>
> >> The site will be running some .cgi and .php scripts and when those 
> >> scripts make changes to the configuration files of the sites, they need 
> >> to be spread automatically to the other two servers. Also when files are 
> >> uploaded to one server, I need them to automatically upload to the other 
> >> servers to.
> >>
> >> What is the best program to do this? Or am I looking at it the wrong way 
> >> and should I do it different?
> >
> > Mirroring is one approach, but here's another:
> >
> > One of the servers holds the data and nfs exports it to the other two.
> > The webroot is on the mounted nfs filesystem. This also eliminates
> > potential data synchronisation problems if you have different
> > filesystems having overlapping/incompatible changes made to them. It
> > lets you invest in one really resilient storage system instead of three
> > possibly inferior ones.
> 
> I don't really understand this approach. Where can I read more about nfs?

man mountd and man exports, together with the handbook:

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-nfs.html

Here's a page with diagrams - it's for a mail server cluster, the
storage is an external raid system and there are two nfs servers, to
provide extra resilience, but the idea is the same:

http://www.shupp.org/maps/ispcluster.html

Peter.