[DRBD-user] DRBD + NFS
danb at zu.com
Sat Oct 14 20:09:15 CEST 2006
On Saturday, October 14, 2006 Mustafa A. Hashmi wrote:
> On 10/10/06, Dan Brown <danb at zu.com> wrote:
> > So while server A is the active NFS server and server B is
> passive and
> > only synching, both servers would mount via NFS server A.
> When server
> > A goes down for whatever reason (reboot, crash, etc) server
> B will take over and
> > continue where server A left off. One thing I keep seeing
> in various
> > documents however is a warning not to have the server mount its own
> > NFS shares. There is never reason (even a vague reason)
> given why not
> > to however. I can see the obvious reasons (eg. infinitely nested
> > filesystems via symlinks/mounts, crossmounts, etc), but my
> directory structures should
> > not need anything like this at all. Other than overall
> system complexity,
> > I don't see any reasons to not be able to self mount NFS
> with a whole
> > lot of trouble.
> Odd -- the NFS-HA howto shows how to do exactly this. Also:
> we've deployed this for mail and web without issues this far,
> albeit, in a non-complex environment.
You mean the one at http://linux-ha.org/HaNFS ? It examples a setup with to
HA NFS servers, and two clients (although not specifiying whether they are
one in the same) . This, along with a fair number of other articles I've
read on using DRBD and NFS all have something like this (from the
"NFS-mounting any filesystem on your NFS servers is highly discouraged."
But none of them ever really give a good explanation(if at all) why.
Having not done much with NFS before, and certainly not in a production
environment, I don't have the experience with NFS to understand many reasons
behind this sort of statement.
danb at zu.com
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