2008-08-04 09:33:08

by Greg Banks

[permalink] [raw]
Subject: Re: high latency NFS

Bernd Schubert wrote:
> On Monday 04 August 2008 03:11:58 J. Bruce Fields wrote:
>> OK, so to summarize: when the rate of incoming rpc's is very high (and,
>> I guess, when we're serving everything out of cache and don't have IO
>> wait), all the nfsd threads will stay runable all the time. That keeps
>> userspace processes from running (possibly for "minutes"). And that's a
>> problem even on a server dedicated only to nfs, since it affects portmap
>> and rpc.mountd.
> Even worse, it affects user space HA software such as heartbeat and everyone
> with reasonable timeouts will see spurious 'failures'.
We're seeing that problem right now, even with the patch.

Greg Banks, P.Engineer, SGI Australian Software Group.
The cake is *not* a lie.
I don't speak for SGI.