Extreme load with local password db lookups

[Patrick van Iersel]

> 
> Jeremy Chadwick schrieb:
>> On Thu, Dec 06, 2007 at 06:22:07PM +0700, Eugene Grosbein wrote:
>>   
>>> On Thu, Dec 06, 2007 at 11:37:50AM +0100, Patrick van Iersel wrote:
>>> 
>>>     
>>>> Here's the situation. We have an web/ftp server with around 74000 users
>>>> defined in the local unix password database. On 4.9-stable which it is
>>>> running now, there is no noticable load when lookups are done (logins via
>>>> ftp, ~user lookups from apache etc.). We want to migrate this system to
>>>> 6-stable.
>>>> However on 6-STABLE (FreeBSD 6.3-PRERELEASE #0: Wed Dec  5 13:35:05 CET
>>>> 2007) these same lookups cause very high load and things slow down to a
>>>> crawl.
>>>> 
>>>> Does anybody have an idea what causes this behavior?
>>>> 
>>>> Thanx in advance for any insights.
>>>>       
>>> Take a look to your /etc/nsswitch.conf. If you do not use NIS,
>>> try to change lines for 'group' and 'passwd' to look like this:
>>> 
>>> group: files
>>> passwd: files
>>>     
>> 
>> The default value is "compat" on both RELENG_6 and RELENG_7.  I don't
>> think switching to "files" will fix his problem (I'll be very surprised
>> if it does).
>> 
> From: Dennis Berger <db at nipsi.de>
> Date: Thu, 06 Dec 2007 13:09:11 +0100
> To: Jeremy Chadwick <koitsu at FreeBSD.org>
> Cc: Eugene Grosbein <eugen at kuzbass.ru>, Patrick van Iersel
> <pviersel at office.caiw.nl>,freebsd-stable at freebsd.org
> Subject: Re: Extreme load with local password db lookups
> 
> A common way to debug is to isolate the affected systemcalls, by using
> tools like ktrace or strace.
> Strace can also record a timestamp, you can see how long it takes to
> complete a specific systemcall
> 
> # strace -r -f <serverproc>
> Do a single login and then examine the results.
> 
> happy debugging.
> 
> regards,
> Dennis


Ok, thanks for the suggestions. I'm a little low on time right now (who
isn't) but I'll work on these next week.

Best regards,
Patrick.