[K12OSN] OT: still have sluggish system

[David Trask]

There was an nscd bug that caused it to die....I'm not sure if it got
fixed....I suspect it did.  When it happened though I found that turning
off nscd solved the issue...and we've also found that unless you have a
LOT of users, it's unnecessary.  also...as for the slow server...I had one
with a hardware conflict that suddenly cropped up in FC4 (previous
versions were fine) I had to add "noapic" and "noapci" to the grub file
menu.lst to get it to run right.  In FC5 the problem seems to be better,
but not solved....so I just got a new server yesterday just like the one
that I'm NOT having hardware issues with (made sure)....so I am
"reprovisioning" it....the new server becomes the K12LTSP box and the
older one becomes the Windows Terminal server.  LOL   Anyway....are you
experiencing things like sluggish video....slow dialog boxes...and so
forth even when actually on the server?  If so it could be a hardware
conflict.


"Support list for open source software in schools." <k12osn at redhat.com>
writes:
>> 
>> The high bandwidth usage is an obvious candidate. Any idea on what is
>> chewing up the bandwidth?
>
>Not really, usage patterns/programs for the teachers/students haven't
>changed much year-to-year.  Software packages are the same as last year. 
>Only change was FC5 upgrade. (mb is Supermicro X5DP8-G2 in case that
>matters somehow)
>
>> 
>> I would also check for authentication/authorization issues (I note in
>> the archives that you use LDAP).
>
>Yep, used David Trask's instructions originally, updated with Matt's
>script later.  Nothing changed though in last year.
>
>> 
>>   Double-check that all of the LDAP configs are correct.
>> 
>
>Everything is as it should be.  Haven't upgraded to latest samba though
>because of concerns with the latest/greatest version of samba and the
>traffic on the samba list about it.
>
>>   Make sure that nscd is running (/sbin/service nscd status)
>> 
>
>Have had an ongoing issue with nscd since like forever.  I am using a
>dual-Opteron server with the prior version of K12LTSP running (x86_64). 
>Fully patched, but I have not upgraded the system to the FC5 version. 
>nscd still dies 2-3 times each day.  A simple restart, or at worse clear
>the database files and restart resolves the issue (on site tech teacher
>has a script that he runs if he sees the authentication stop). I am
>planning to move my LDAP server to a new 32-bit system just to get away
>from this issue.
>
>>   Make sure that DNS is correct (/etc/resolv.conf)
>> 
>
>Haven't touched this either, but will recheck.
>
>> 
>> I'd also check the disk sub-system...
>
>I did upgrade from Ultra160 IBM Deathstar drives (they were dirt cheap
>and now I know why) to Ultra320 Seagate Barracuda's.  Was using a
>zero-channel controller for RAID-1 on the OS drives, but ... that is
>another thread. :)  Now using software RAID-1 on one system, nothing on
>the other (skating on thin ice).  Both systems show the same issues.
>
>> 
>>   Run "dmesg" and look for SCSI errors
>> 
>Haven't seen any so far.  Checked earlier, will check again.
>
>>   Run "sar -b" to see the disk I/O usage patterns
>>   (if you don't have "sar", install it with "yum install sysstat")
>> 
>have to install and test this as well.  Only issue is that I am running
>out of annual leave to spend at the school troubleshooting this.  The
>issues only show up under load.  Still, will be there tomorrow morning
>bright and early since it is my day off :)
>
>Sincerely, and thankfully,
>Dave ...
>
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David N. Trask
Technology Teacher/Director
Vassalboro Community School
dtrask at vcsvikings.org
(207)923-3100