Date: Thu, 24 Sep 2015 10:03:09 +0200 From: Frank de Bot <lists@searchy.net> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: freebsd-stable@FreeBSD.org Subject: Re: kernel process [nfscl] high cpu Message-ID: <5603AE3D.5090407@searchy.net> In-Reply-To: <1031959302.30289198.1430594914473.JavaMail.root@uoguelph.ca> References: <1031959302.30289198.1430594914473.JavaMail.root@uoguelph.ca>
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Rick Macklem wrote:
> Frank de Bot wrote:
>> 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?
>>
> Well, the nfscl does server->client RPCs referred to as callbacks. I
> have no idea what the implications of running it in a jail is, but I'd
> guess that these server->client RPCs get blocked somehow, etc...
> (The NFSv4.0 mechanism requires a separate IP address that the server
> can connect to on the client. For NFSv4.1, it should use the same
> TCP connection as is used for the client->server RPCs. The latter
> seems like it should work, but there is probably some glitch.)
>
> ** Just run without the nfscl daemon (it is only needed for delegations or pNFS).
How can I disable the nfscl daemon?
>
> Since a big Netapp filer (the cluster ones) are about the only servers
> that currently support pNFS (no FreeBSD server support yet), you can
> probably forget about pNFS (I'd get rid of the "pnfs" mount option).
> It also won't work unless this callback path is working.
>
> As for delegations, they aren't required for NFSv4.[0-1] to work correctly
> and aren't enabled by default on the FreeBSD server.
> --> Running without the nfscl daemon will just ensure no delegations
> are issued, even if enabled on the server.
>
> rick
>
>>
>> Regards,
>>
>> Frank de Bot
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