Re: CPU utilisation = 99% => death; help, please!

[Nick Urbanik <nicku@vtc.edu.hk>]

John Madden wrote:

> > we have set up OpenLDAP v2.0.15 on RH Linux 7.1 on a 2 CPU 800MHz Acer
> > box.  We are authenticating about 5000 users with LDAP, with automount
> > home directories.  We are providing password, group and automount info
> > to our laboratories.  We have up to 200 users on the system at once.
> > LDAP stops several times a day.  I watched this happen on /usr/bin/top
> > today; usage went up to 99%.  I am working arround this using a cron
> > job that checks the output of ps and restarts ldap if necessary, but we
> > have a serious problem, and after reading all the documentation, am
> > unsure what to do next.  I am now running 2.4.10-ac12, but have tried
> > many kernels.
>
> I understand 2.4.10 has serious issues with network load and simply dying,
> so you might try 2.2.19 as it's much more stable than anything in 2.4, but I
> doubt that's the problem here.

I am using Alan Cox's kernels, which I have found to be okayish; they do not
include the wildest changes introduced into Linus' kernels.  For what it's
worth, slapd has not died since I rebooted into 2.4.10-ac12.

> First off, show us some more debugging.  Is it a segfault?  Is it being
> killed by the kernel OOM killer?

That is my question: how to identify what is happening?  I noticed that memory
consumption was modest while the CPU load was so high.

> As for the 99% cpu thing, you probably need some more indexes.

Thank you!   Right, I think that is probably the right thing to investigate.
How can I find what the server is looking up?  How do I get stats on what it is
doing?

I know these are basic FAQ type questions, but none of the many docs I've read
have given me much of an indication.

--
Nick Urbanik   RHCE                                  nicku@vtc.edu.hk
Dept. of Information & Communications Technology
Hong Kong Institute of Vocational Education (Tsing Yi)
Tel:   (852) 2436 8576, (852) 2436 8579          Fax: (852) 2436 8526
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