Re: NFSv4 first read/write takes 1 minute to start
Jonas Meurer <jonas@freesources.org> writes:
> Hi Mart,
>
> Am 28.06.2015 um 21:40 schrieb Mart van de Wege:
>> I run a fileserver and am trying to switch over from NFSv3 to NFSv4 with
>> RPC-GSS. My exports work, and my clients nicely authenticate to the
>> Kerberos server and the NFS server, I can mount the exported filesystems
>> and cd into them.
>>
>> But as soon as I try to read or write anything on the mounted
>> filesystem, I get a timeout of 1 minute. After that, all other reads and
>> writes on the mounted filesystem proceed normally.
>
> I cannot help you with a comprehensive explanation, but at least I
> discovered similar timeouts while fiddling around with my new
> NFSv4+Kerberos setup. The first operation on a fresh mounted NFS share
> took ages (one minute is quite possible). I don't remember whether it
> timeouted or succeeded in the end.
>
> Now that everything is in place and working as expected, I no longer
> discover these timeouts. Every operation (read+write) to the NFS share,
> starting with the first one, finishs within milliseconds.
>
Well, it gets worse. After a day I tried it again, but from work over a
VPN. This time the first write operation (touching a test file) finished
within the bounds of the speed of the VPN connection.
So apparently some old information got cached somewhere and invalidated
by the passing of time.
On Thursday I am back on location, I will check again to see if the
problem persists at local network speeds.
>> I tested it with sec=sys, and that shows no difference. Mounting goes
>> fine, cd goes fine, first operation hangs.
>
> Do you have your PTR records set correctly? Not sure whether it is
> related, but apart from fixing Kerberos principal mapping and ticket
> cache handling, the missing PTR record for my Kerberos/NFS server was
> one of the last things I fixed.
>
It's my home/development server; it runs on an entirely internal zone,
with full and correct PTR records. It's been running Kerberos for years
now for other services, and incorrect DNS has already bitten me in the
past.
--
"We will need a longer wall when the revolution comes."
--- AJS, quoting an uncertain source.
Reply to: