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

email builder wrote:
>
>
> 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.

>>>> 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.

>>>>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.


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