Rare ELException

[Brian Moon]

Using the Prefork MPM since that is the default MPM with SLES and I really
had not given it much thought.  I'll check out the Event MPM and see if
that would make sense for us to switch to.

As for keep alive, it is on with the following settings:

   - MaxKeepAliveRequests 100
   - KeepAliveTimeout 15

Anyways, the point of this was not to critique the settings but to say I
found a way to reproduce the ELException.  What exactly in the stress test
is causing it I do not know, but it has consistently shown up a few times
during the testing.


Brian Moon
Senior System Administrator
Enterprise Systems
Santa Clara University
Office: 408.554.4830
bmoon at scu.edu

On Thu, May 18, 2017 at 5:20 PM, Cameron Kerr <cameron.kerr at otago.ac.nz>
wrote:

> I would wonder why you use the Prefork MPM with Apache 2.4 instead of say
> the Event MPM, which is much more scalable. I would also suggest that
> enabling Keepalives (with a reasonably short lifetime) would also help with
> scalability and cut down on port utilisation.
>
>
>
> Cheers,
>
> Cameron
>
>
>
> *From:* users [mailto:users-bounces at shibboleth.net] *On Behalf Of *Brian
> Moon
> *Sent:* Friday, 19 May 2017 11:54 AM
> *To:* Shib Users <users at shibboleth.net>
> *Subject:* Re: Rare ELException
>
>
>
> Hello all,
>
>
>
> While stress testing one of our IdP servers today we were able to
> reproduce this error.  Below is some information about our environment and
> the testing parameters:
>
>
>
> IdP Server:
>
>    - SLES 12 SP2
>    - IdP Version 3.3.1
>    - Oracle JDK 1.8.0_112-b15
>    - Tomcat 8.0.36-20.7
>    - JAVA_OPTS: -Xms3g -Xmx3g -XX:MaxGCPauseMillis=400
>    -XX:+DisableExplicitGC -XX:+UseG1GC
>    - 2 Cores
>    - 6 GB RAM (VM memory reservation set to reserve all guest memory)
>    - Apache 2.4.23-21.1
>
>
>    - Apache Prefork MPM
>       - ServerLimit 5120
>       - MaxClients 5120
>
> Testing VM:
>
>    - Windows 7 Enterprise (64-bit)
>    - 4 Cores
>    - 8 GB RAM
>    - Oracle JRE 1.8.0_131-b11
>    - Apache JMeter 3.2 r1790748
>
>
>    - Test plan: https://wiki.shibboleth.net/confluence/download/
>       attachments/17072886/shibboleth-unsolicited-sso-test.jmx?version=2&
>       modificationDate=1435784363124&api=v2
>       <https://wiki.shibboleth.net/confluence/download/attachments/17072886/shibboleth-unsolicited-sso-test.jmx?version=2&modificationDate=1435784363124&api=v2>
>       - ThreadCount 1500
>       - Duration 300
>       - RampUpPeriod 10
>       - ProviderId https://sp.testshib.org/shibboleth-sp
>
> For the Apache config on the IdP server, the ServerLimit and MaxClients
> were set to something ridiculous so we could see what kind of load it could
> take.  On the testing VM we were running out of ephemeral ports, so we
> added a registry key to increase the max port number that could be used by
> a user: https://www.baselogic.com/blog/solved-java-net-
> bindexception-address-use-connect-issue-windows/ (this is not needed to
> reproduce the error, but cuts down on some noise).  We did still have some
> socket errors on the testing VM, but overall it seemed to run a lot better.
>
>
>
> Hope that helps in reproducing this and tracking down the cause.
>
>
>
> Brian Moon
> Senior System Administrator
> Enterprise Systems
> Santa Clara University
> Office: 408.554.4830 <(408)%20554-4830>
> bmoon at scu.edu
>
>
>
> On Mon, Apr 24, 2017 at 9:26 AM, Cantor, Scott <cantor.2 at osu.edu> wrote:
>
> > Yes, I'm currently waiting for my session to timeout on the login form
> so I can
> > see what it does. I would expect it to throw a flow execution error
> though, so
> > I don't know if that's going to do it. I also see *very* few of these in
> my log,
> > like once a day or so, and that's with a decent volume, so that's
> puzzling.
>
> A basic "Wait too long" timeout doesn't have anything to do with this
> error, so that's as expected. So I have no idea how one would reproduce it.
>
> -- Scott
>
>
>
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