[K12OSN] OT: still have sluggish system

Tue Sep 12 18:50:54 UTC 2006

Dave,

Turn off nscd. Add entries in /etc/hosts for the authentication
server(s). Check /etc/nsswitch.conf for lookup ordering on DNS and
authentication. DNS lookup should be set to "hosts: files dns" in
nsswitch.

Check "/sbin/chkconfig --list"  for a list of all services that are on
at boot up. Turn off everything that is not used with "/sbin/chkconfig
<service name> off"

Check in /etc for multiple nsswitch.conf files. Be sure the correct one
is in use. Scan for rpmold and rpmnew.

Then reboot the machine(s) and go to the closet and unplug the client
connection to the switch. See if the load spikes on the server. If it's
OK, start plugging in segments to see if the switch is bogging down and
if so, on what segment. Keep an eye on the server load.

Also check the /etc directory for multiple dhcpd.conf files. K12LTSP v.5
uses a differently named file than dhcpd.conf.

Lastly, check the clients to see what video driver they are running. If
they are using the old vesa driver, that is a hog (painfully slow) and
could be a primary detractor. K12LTSP v.5 now uses xorg and not xfree.
Some older stuff has been dropped.

On Tue, 2006-09-12 at 18:06 +0000, dahopkins at comcast.net wrote:
> This may read like a rant, but isn't.
> 
> I have tried turning off nscd.  When I do this, authentication stops.  It doesn't make sense, but that is what happens.  The typical usage pattern is that around 60-70 users try to log onto the systems in a 1-2 minute timeframe every 45 minutes.
> 
> The Tech Coord at the school just called me to let me know he is ready to quit.  :(  For 3 years this has worked flawlessly (well, sound synced with video would be nice, but ..; ), now these issues.  Users can log in, just that anything that is network intensive runs very slowly now. Still notice that at the server, the load can hit 2 with just the console and two other users logged on.  The systems are not using swap, so memory isn't it.  Just these network-related issues it seems.
> 
> There is something going on with the network that is saturating my gigabit switch.  The activity lights are almost solid at times.  But, it is isolated to the switch.  Maybe the switch is having issues, don't know.  Have completed virus scans, malware, etc with no positive leads.  None of the NICs on any servers are showing dropped packets, just a lot of traffic.
> 
> I am going to start turning off services until the network goes quiet and see if that tells me something. 
> 
> Sincerely,
> Dave Hopkins
> 
> 
>  -------------- Original message ----------------------
> From: "David Trask" <dtrask at vcsvikings.org>
> > How many users do you have?  If you have less than 1500 or so....don't
> > bother with nscd...turn it off.
> > 
> > "Support list for open source software in schools." <k12osn at redhat.com>
> > writes:
> > >Update on system sluggishness.  Over the last few days, more
> > >troubleshooting seems to indicate that the issue is somehow tied into
> > >authentication.  nscd is (still) constantly dying on the authentication
> > >server.  Also, there are literally over a thousand ldap entries showing
> > >up in the output from netstat on the sluggish system.  Many are in a
> > >CLOSE_WAIT state.  On a reboot, there are just a couple but after 20-30
> > >logins, it starts going up quickly.
> > >
> > >At this point, I am going to run Matt's ldap script on the 'new' FC5
> > >K12LTSP server and just move authentication over to it.  Hopefully this
> > >will be straightforward.  I have some concerns with authentication on my
> > >Windows systems (issues with latest version of samba), but ... what the
> > >heck,  who needs sleep. ;)
> > >
> > >Thanks for the advice, it has helped to point out some possible issues.
> > 
> > 
> > David N. Trask
> > Technology Teacher/Director
> > Vassalboro Community School
> > dtrask at vcsvikings.org
> > (207)923-3100
> > 
> > 
> > _______________________________________________
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> > K12OSN at redhat.com
> > https://www.redhat.com/mailman/listinfo/k12osn
> > For more info see <http://www.k12os.org>
> 
> 
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-- 
James P. Kinney III          
CEO & Director of Engineering 
Local Net Solutions,LLC        
770-493-8244                    
http://www.localnetsolutions.com

GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
<jkinney at localnetsolutions.com>
Fingerprint = 3C9E 6366 54FC A3FE BA4D 0659 6190 ADC3 829C 6CA7
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