[DRBD-user] DRBD + NFS

[Dave Dykstra]

On Sat, Oct 14, 2006 at 12:09:15PM -0600, Dan Brown wrote:
> On Saturday, October 14, 2006 Mustafa A. Hashmi wrote:
> > On 10/10/06, Dan Brown <danb at zu.com> wrote:
...
> > > 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
> linux-ha.org page): 
> 
> "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. 

The biggest problem was with the fuser command hanging.  I have updated
that web page to link to the mailing list threads where the problems
were detailed.

- Dave