nfsd server cache flooded, try to increase nfsrc_floodlevel

[Mike Shultz]

I ran into an issue today of our server thinking that it was being
flooded and locking our nfs users out. Got a LOT of these messages:

Jul 12 16:08:22 xxxxx kernel: nfsd server cache flooded, try to increase
nfsrc_floodlevel

Our server(`uname -a`):  FreeBSD xxxxx 8.2-RELEASE-p2 FreeBSD
8.2-RELEASE-p2 #0: Tue Jun 21 16:52:27 MDT 2011
yyy at xxxxx:/usr/obj/usr/src/sys/XXXXX  amd64

I could find no information on nfsrc_floodlevel other than source code
which didn't explain too much about it. I don't know if it's a kernel
config var, or what.

`nfsstat -e` did show this:

CacheSize   TCPPeak
    16385     16385

So I'm guessing that that is the current cache limit.

The source code and this output suggest that we're just running into the
limit. However, a comment in that source does suggest that "The cache
will still function over flood level" but that doesn't seem to be the
case. I ended up having to revoke the clients and restarting nfsd to get
it operational again.

I would appreciate anyone that could clarify what nfsrc_floodlevel is
and how to go about changing it.

-- 
Mike Shultz
Information Technology Assistant
Project Vote Smart

Phone: 406-859-8683
Toll Free: 1-888-VOTE-SMART
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