[K12OSN] Firefox and load average

[David Hopkins]

I'll try changing the file limit (once I go find that discussion
again). Users haven't changed and browsing behavior hasn't changed.
The big thing seems to be that one server is running K12LTSP 4.2 and
the another is running CentOS 5.  I haven't had time to upgrade the
K12LTSP server, so what is really annoying is that if they log onto
one server, launch FF (same version on both systems), it takes a while
to launch. Then, if still on that server it launches quickly from then
on. BUT if they then change and use a thin client connected to the
other server, the launch again takes a while (30-60 seconds) before it
starts.  Seems to be some sort of issue with having different OS's
between the two servers.  It is 100% repeatable.  I'll try loading
Opera as a test, and over Christmas upgrade the K12LTSP server (unless
I can do so this weekend instead).

There aren't any stale processes or other issues.  Just the 30-60
second lag in launching each time they switch servers.

Thanks!
Dave Hopkins

On Dec 4, 2007 11:15 AM, Jim Kronebusch <jim at winonacotter.org> wrote:
> On Mon, 3 Dec 2007 13:08:22 -0500, David Hopkins wrote
>
> > Just recently (last few days) when students launch FF (1.5), the load
> > average on the server will spike to 20 or so, sometimes much higher,
> > (on a dual 2.4GHz hyperthreaded Xeon system), then over a few minutes
> > come back to 2 (more or less). The problem is that during the spike,
> > everything comes to a complete crawl.  Since this behavior has only
> > started recently, I am at a loss for why. I have not updated any
> > packages nor added any.  It is almost like some 'tipping point' was
> > reached wrt files, perhaps related to a thread discussion earlier
> > concerning open files?  Has anyone else on the list seen behavior like
> > this? And if so, have a recommendation on how to resolve it?
>
> For what it is worth I don't think my processor usage spiked when the open file limit
> was reached.  However things did slow and prevented any new logins until enough users
> logged out and the file limit was no longer exceeded.  The limit I believe was due
> solely to the fact that I use LDAP users.  If you don't use LDAP it is unlikely that you
> see this problem, I also had 75 or more concurrent users to reach this limit plus email
> sessions from a different server.
>
> However if you use LDAP you may just want to try increasing the file limit to see if it
> helps, you need to reboot the server to be certain it takes effect.
>
> I assume the amount of students concurrently logging in hasn't changed.  Did you or the
> students change the homepage?  If so the extra graphics loading of if the new pages
> contain flash, this might be causing a problem.
>
> Are there any stale process left on logout?
>
> Just some thoughts,
> Jim
>
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