[CentOS] how to unmount an NFS share when the NFS server is unavailable?

Thu Jan 27 21:23:38 UTC 2011
Dr. Ed Morbius <dredmorbius at gmail.com>

on 07:54 Thu 27 Jan, John Hodrien (J.H.Hodrien at leeds.ac.uk) wrote:
> On Wed, 26 Jan 2011, Dr. Ed Morbius wrote:
> > I'd suggest the automount route as well (you're only open to NFS issues
> > while the filesystem is mounted), but you then have to maintain
> > automount maps and run the risk of issues with the automounter (I've
> > seen large production environments in which the OOM killer would
> > arbitrarily select processes to kill ....).
> Once you're into an OOM state, you're screwed anyway.  Is turning off
> overcommit a sane option these days or not?

Our suggested fix was to dramtically reduce overcommit, or disable it.
I don't recall what was ultimately decided.

Frankly, bouncing the box would generally be better than letting it get
in some weird wedge state (and was what we usually ended up doing in
this instance anyway).  Environment was a distributed batch-process
server farm.  Engineers were disciplined to either improve memory
management or request host resources appropriately.

Now, if you were to run monit, out of init, and restart critical
services as they failed, you might get around some of the borkage, but
yeah, generally, what OOM is trying to tell you is that you're Doing It

Dr. Ed Morbius
Chief Scientist
Krell Power Systems Unlimited