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Re: [K12OSN] Client RAM requirements? / Athalon ATA server vs.Dual-Xeon with SCSI - feedback?



Here is our experience with 35 clients.
Specs:

Dual PIII 933, 2GB RAM, 3  18 GB SCSI  W/ Hardware RAID 5
10/100 NICS on all
2 24 Port SMC Switches.
Clients P 133 - P II 233 all have 32 - 160 MB RAM

We very little swapping taking place.

Sitting side by side is one P 133 32 MB RAM and a PII 233 with 160 MB
RAM both have 8 MB Video RAM. The performance is identical 

Performance is excellent up to 24 clients.

After 24 clients the %Processor Utilization starts climbing and when it
reaches 80% the performance is very slow, it will peak at 97 to 98 %
then drop down to about 65% at which point the performance is
acceptable.
 
Staggering log-ons and launching Mozilla / OpenOffice in groups of 10 in
15 to 30 second increments helps a great deal in getting all 35 clients
to a working OpenOffice / Mozilla desktop in short order.

A couple of impatient students triple clicking on Mozilla bogs down the
system.

We started with 1 GB RAM and doubled it, this didn't make noticeable
difference during the log on process.

My hunch is a network bottleneck might be responsible for the high
processor utilization.We might try adding a 3rd NIC one for each switch.

As for video RAM this has been my observation, anything less than 8 MB
has resulted in less than adequate redrawing of windows. I noticed sort
of a strobe effect ie. there is a pause then the window is smaller
another pause then the window is smaller again and so on. 

For those using a 1000 MB NIC I'd be interested to know the performance
change after adding it. Can it be throttled back to 100 then back up to
full speed in order to gage the performance increase? 


I'd like to note that as long as everyone does not log on at the exact
same time and launch apps at the same time the system works very good.
Our overall experience has been very good and we are currently trying to
get the funds together to put 3 or 4 clients into every classroom.

Well that's my .02 worth and it goes without saying YMMV.

Eric and Paul, you guys have done quite an amazing thing here with
K12LTSP. 

Happy Memorial Day. Remember the Vets.


John

On Mon, 2002-05-27 at 01:09, Greg Long wrote:
> I am getting involved with our local schools to explore the possibility
> of a K12LTsP deployment. After some initial reading, it appears for
> K12LTSP (2.0.2 ISO's just downloaded) almost any old legacy box can
> become a client.
> 
> My main question is how much RAM is required?  I should think if
> everything runs from the server, even 4 or 8mb RAM would do fine, and
> even a pentium 75 with a 2mb DRAM PCI video would perform nicely with a
> 100bT NIC.  We can most likely make extensive use of existing clients.
> 
> Attached is some ballparking I did for a single CPU Athalon Server for a
> target of 12 clients utilizing 3 ATA/100 drives and a Dual Xeon for a
> target of 24 clients.  The prices come from a little poking around on
> pricewatch - with the recognition that we may pay a little more in one
> area and skimp a little in another.  My thought is that is due to the
> larger storage space per dollar (as well as client) the IDE drives might
> be a favorable option over the SCSI drives. 8.7ms seek for 12 clients vs
> 5.2ms seek for 24 clients is the number that really seems to make this
> acceptable - plus the estimated cost per client.  I am also figuring
> putting a separate 9 or 10gb drive for a swap-only partition should help
> out the whole equation.  128mb/client ought to help reduce swapping in
> the first place, until client load gets heavy. Certainly a smaller drive
> than a 10gb 7200rpm IDE
> 
> The Xeon server could also be built more cheaply - such as 1.7 Xeons, or
> even a single CPU Xeon.  From the reading, I've been getting the
> impression that CPU load isn't really the performance bottleneck, but
> rather the RAM and seek time of hard drives.
> 
> I'll be setting up a test K12LTSP server soon at home to play with all
> this on a 1.2 Athalon /ATA100 drive and 3 or 4 existing Winboxes of
> various speeds, booting to floppy to connect to the server - I'm not up
> on how to configure those yet for the various Xf86 drivers, but I'll
> read the documentation. :)
> 
> Another question, on the site, it was mentioned that 2 SCSI drives were
> suggested for the larger server - one for /home, although I think in the
> example /home was mounted on another server's SCSI.  I'm thinking
> putting /home on the same box should not adversely affect performance
> too much.
> 
> Finally, and this is a bigger curiosity than some of the others:
> Network congestion.  Pushing graphics over a 100bT can get slow.  Not
> being too knowledgeable about X, my experience with this is limited to
> running VNCserver/client over my 100bT here - but I'm the only user.
> With 24 or 32 active clients, isn't the network a limiting factor?
> Would performance be noticeably increased with just 12 clients?  
> 
> I'd welcome any feedback on these 6 issues as described above:
> 
> 1) RAM/CPU for clients
> 2) IDE vs. SCSI
> 3) Athalon vs. Dual Xeon
> 4) Separate swap drive - would it help?
> 5) /home on separate drive on same box
> 6) Network congestion with 24 or 32 clients vs. 12 clients
> 
> Big thanks,
> 
> Greg Long
> Klamath Linux Unix Group
> http://www.maneuveringspeed.com/klug/index.html 
> ----
> 















































































































.00
(est)
























































Total


$1,212.00




$2,906.00
















Average
cost per
client


$101.00




$121.08
















RAM
(mb/client)
128.0




85.3














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