kernel process [nfscl] high cpu

[Frank de Bot (lists)]

Hi,

On a 10.1-RELEASE-p9 server I have several NFS mounts used for a jail.
Because it's a server only to test, there is a low load. But the [nfscl]
process is hogging a CPU after a while. This happens pretty fast, within
1 or 2 days. I'm noticing the high CPU of the process when I want to do
some test after a little while (those 1 or 2 days).

My jail.conf look like:

exec.start = "/bin/sh /etc/rc";
exec.stop = "/bin/sh /etc/rc.shutdown";
exec.clean;
mount.devfs;
exec.consolelog = "/var/log/jail.$name.log";
#mount.fstab = "/usr/local/etc/jail.fstab.$name";

test01 {
        host.hostname = "test01_hosting";
        ip4.addr = somepublicaddress;
        ip4.addr += someprivateaddress;

        mount = "10.13.37.2:/tank/hostingbase      /opt/jails/test01
   nfs     nfsv4,minorversion=1,pnfs,ro,noatime        0       0";
        mount +=  "10.13.37.2:/tank/hosting/test
/opt/jails/test01/opt       nfs     nfsv4,minorversion=1,pnfs,noatime
     0       0";

        path = "/opt/jails/test01";
}

Last test was with NFS 4.1, I also worked with NFS 4.(0) with the same
result. In the readonly nfs share there are symbolic links point to the
read-write share for logging, storing .run files, etc. When I monitor my
network interface with tcpdump, there is little nfs traffic, only when I
do try to access the shares there is activity.

What is causing nfscl to run around in circles, hogging the CPU (it
makes the system slow to respond too) or how can I found out what's the
cause?


Regards,

Frank de Bot