Antw: Re: AW:ldap server stops responding periodically?

["Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de>]

>>> John Jasen <jjasen@gmail.com> schrieb am 20.07.2018 um 15:41 in Nachricht
<2b16aef8-a174-2ae4-f113-45cc6a414a49@gmail.com>:

> 
> On 07/20/2018 04:41 AM, Ulrich.Windl@rz.uni-regensburg.de wrote:
>> Hi!
>>
>> Stupid question: could it be your load-balancer that had a problem?
>> How does the netstat look like (sockets opened, queued data, etc.?)
> 
> I do not believe it to be the load-balancer. They log loss of contact
> with the LDAP servers and drop them from the relay group shortly after
> one of these events start; and when it gets cleaned up, they're added
> back in. I also do not suspect network between the load balancers and
> the LDAP servers.
> 
> During such an event, ps -efT will usually show slapd running at full
> thread capacity. Comparing that to threads in cn=monitor is not
> possible, as those ldap searches fail.

Still I don't know the internals on slapd, but could it runs out of worker threads? DO you monitor the theads' activity up to the problem?

> 
> Open sockets does not substantially change until after the event
> subsides. The servers will show 1200-2000 open sockets before an event,
> and drop lower when it clears up -- to quickly scale back up to
> pre-event levels.

The other idea is to try to run "strace ... -p pid" on the hanging process to see what it is doing, or maybe even try to attach gdb to the process (most useful if the binary still contains debug info).

> 
> The queues will show data being held until the socket(s) time out.

OK, so it des not look like a problem in the load-balancer.

Regards,
Ulrich