Re: [courier-users] NFS server load thru the roof

> > We have not tried non-reiserfs over NFS, although we have before we moved
> it
> > to NFS and we did not have this issue. We tried the noatime option
> briefly
> > and the iowait spiked right back up after remounting.
>
> I've never used ReiserFS on an NFS server, so I'm not sure if there are
> issues or not. I think I recall that it took a long time for the kernel
> developers to get NFS working at all on Reiser.

Huh. Interesting.

> >>>> Briefly, mail spool is mounted over NFS, everything runs smoothly
> until
> >>>>we
> >>>>turn IMAP on and server load goes off the scale (NFS client load 300,
> NFS
> >>>>server load 10, with server in wait about 80% of the time).
> >>
> >>How many users are connecting to the NFS client host at the same time?
> >>If you run 'ps ax' on that host, you should see ~300 processes in R or D
> >>state. What are they?
> >
> > Lots of nfs processes is ps, but that's cuz we run 128 of them. 16 in
> state
> > D, 115 in state S, none in state R. (looks like the total doesn't match
> up
> > but you get the idea) Is this abnormal. Our stats on the mail server
> show
> > at this time that there are 20-25 concurrent users using IMAP.
>
> I think you're talking about the NFS server host. I was asking about
> the client. If the load is 300, then there should be ~300 processes in
> R or D state.

Sorry. Well, our load has calmed down, interestingly enough. It is still
high (~10) but nowhere near 300 any more. But Courier IMAP performance is
still abysmal and the only stat that is meaningful to me is that the NFS
server is at 90%+ iowait. So it might not be Courier, however, turning it
off relieves the problem, even when postifx/courier-maildrop are delivering
lots of messages to the mount.

Is there any switch to ps that can pull out the ones in R or D state?


> >>>>I am guessing it is more of a NFS
> >>>>configuration thing, or possibly something with our file system on the
> >>NFS
> >>>>server (reiserfs and RAID 5), but I'm a little wet-behind-the-ears on
> >>that
> >>>>front, so even some baby hand-holding by someone who has the time and
> >>>>patience would be highly appreciated. I mean, I don't even know if the
> >>>>"sync" option for our mail spool NFS mount is best turned off....?
> >>
> >>"sync" is off by default, and should remain so.
> >
> > I read some more on this. sync is only off by default on the client, but
> is
> > on by default on the server.
>
> Oh, you meant NFS. I thought you were talking about the mount option
> for ReiserFS. "sync" is default for NFS, and that should probably be
> left alone, too.

Where can we verify the reiserfs sync settings then?

THANK YOU!




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