Re: nfsd problems with FreeBSD 5.2.1

From: Mike Thomas <mwt_at_cems.umn.edu>
Date: Fri, 16 Jul 2004 14:02:43 -0500
Eric,

It's not a dell, its a 1U box from Sun with x86 hardware, I believe the 
model on it is V60x, but no, I haven't tired turning off hyperthreading, 
that's one thing I am about to do. I have backed out from 5.2-current to 
RELENG_5_2 to go back to 5.2.1-release and I'm going to see if that 
helps at all.

--Mike

> Oh - and also - have you tried turning off hyperthreading?  is this a 
> Dell by any chance?
>
>
> Mike Thomas wrote:
>
>> Hello,
>>
>> Alright folks, I'm in some serious need for help/advice.
>>
>> I'm running FreeBSD 5.2.1 (-current) with a kernel/buildworld ran 
>> yesterday (7/16/2004) on a Dual Xeon 3.06ghz with hyperthreading 
>> enabled. The machine also has 2gb of ram and a scsi raided array with 
>> an intel storage raid array controller. (iir0)
>>
>> The machine functions as a nis client for accounts with home 
>> directories nfs mounted from a Solaris 9 machine. It's primary 
>> function is as a mail server, and what it is nfs sharing out is the 
>> spool folder. (/var/mail, in this case).
>>
>> I know all about the dangers of sharing out a mail spool, I don't 
>> need, or want, a lecture about proper operating procedures in this 
>> case. It's for legacy purposes and will be going away in due time. 
>> Anyway, its with this mount that I am experiencing these nfs problems.
>>
>> Now, to the nitty gritty. I am seeing periodic spikes from one of the 
>> nfsd children from about 10% of the cpu (via top) to 100% of the cpu. 
>> During times of this spike, even if the spike only reaches 40-50% of 
>> the cpu, the machine becomes dibilitatingly slow and stops responding 
>> to all other commands. Even issuing an 'ls' is difficult, let alone 
>> doing anything productive. While using top, the nfsd state will 
>> alternate between biowr, biord, *Giant (yeah, it even is requesting 
>> Giant locks). I have recompiled every single ounce of software that 
>> operates on /var/mail to only use fcntl locking 
>> (procmail/postfix/uw-imap (there's a patch by redhat to do that)) so 
>> that it is nfs friendly.
>>
>> Here's what I've tried to do to see if it made any difference. First, 
>> all mounts of /var/mail from other servers were using UDP, they have 
>> all been switched to tcp with a rsize and wsize of 1024. I've tried 
>> 4096, and 8192, both which make no difference. All clients are 
>> specifically forced to use NFSv3. I have also tried varying between a 
>> soft and hard mount, also, with no difference in these spikes.
>>
>> I also tried switching back to the 4BSD scheduler, to see if that 
>> might have beeen the issue, but it would appear that didn't make any 
>> difference as well, though the max load average I was seeing stayed a 
>> bit lower with ULE as upposed to the 4BSD scheduler.
>>
>> So, I'm really at the end of my rope right now, I have no idea what 
>> to do or what could be causing this. Any advice would be great, thanks.
>>
>> --Mike
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>
>
>
>
Received on Fri Jul 16 2004 - 17:02:48 UTC

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