[K12OSN] 8 GB RAM on 32-bit Edubuntu with AMD 64 processors

[Jim Kronebusch]

On Mon, 26 Nov 2007 13:46:55 -0500 (EST), Tom Wolfe wrote
> .... So Jim what do you have to say about this?? From what I recall you 
> report good performance with PAE/LTSP and 16 GB RAM with 100+ users.
> 
> Regards,
> Tom Wolfe

Sorry for the slow reply.

I server 108 terminals from my single LTSP server running Edubuntu 7.04 and the
linux-image-server kernel version 2.6.20.16.28.1.  I have seen 75 concurrent users all
running Firefox with Adobe Flash and OpenOffice and have seen max processor usage at
less than 25% and RAM at I believe 6GB or so.  Whether or not PAE takes a performance
hit over 64-bit, I'm sure that it true, how much, nobody seems to know for sure.  But I
assure my setup is running great, and the screen resolutions are at 1280x1024.  Sound
works great.  I did try all the tricks with K12LTSP based LTSP, all the 32-bit firefox
tricks or using nspluginwrapper to tie 64-bit firefox with 32-bit supporting apps worked
flawlessly.  However under Ubuntu this was not the case.  The only way I was able to get
working sound in flash 9 on the thin clients under Firefox was with 32-bit OS and 32-bit
apps, nothing else worked.  I had all tricks for libflashsupport, nspluginwrapper, you
name it, no sound in flash 9.  This is why I went the way of PAE to support my RAM and
processors with the linux-image-server kernel.  Everything worked, and all RAM available.

Now, it isn't like I'm running this many users on a dual PIII box with 16GB RAM.  I'm
running a Dual Quad Core 2.66Ghz Xeon box (a total of eight 2.66Ghz cores).  I also run
6 300GB 3Gbps SAS drives in RAID 10 and 6 GB NICs teamed in alb for network throughput.
 And 16GB RAM.  So if there is a performance hit, this might be why I don't see it.

So to enable PAE in your 32-bit Edubuntu server, "sudo apt-get install
linux-image-server", when finished reboot and be sure it grabs your new kernel.  Then
verify all processors and RAM show up.  If the performance isn't good enough, then scrap
flash and go 64-bit.  Hopefully as the new local app support develops this will become a
non-issue.  I plan on moving Firefox, flash, java and any other possible 32-bit apps
local in the future, then run a strict 64-bit server.

Hope this helps.

Jim

-- 
This message has been scanned for viruses and
dangerous content by the Cotter Technology 
Department, and is believed to be clean.