[K12OSN] Performance Issue

Petre Scheie petre at maltzen.net
Fri Mar 24 15:08:05 UTC 2006


Clustering and app servers are different things.  An app server just means you dedicate 
a server to providing one application.  Since X Windows allows programs to run on one 
machine and display on another, this is quite easy to do (hey, maybe someone could build 
a system where all the apps run on one server and the clients could even get their 
operating system from that server!  What?...Oh, never mind. ;-))  Clustering means have 
a bunch of machines act as a single system.  It's good for redundancy and problems that 
lend themselves to parallel processing, but I think their use in LTSP settings has had 
mixed results at best.

Setting up an app server is pretty simple:

-Install the same version of k12ltsp on the app server as you have on your terminal 
server, to keep things simple.
-Create the same user IDs on the app server as exist on the terminal server.
-NFS export the /home directory from the terminal server.
-Mount that /home directory under /home on the app server.
-Generate SSH keys for all users using the ssh-keygen program, and copy the id_rsa.pub 
file into the authorized_keys file in each users ~/.ssh/ directory.
-Setup an icon that calls the app on the app server thusly: ssh appserver ooffice
-Push this icon to all users.

Gavin Spurgeon wrote a simple how-to on app servers a while back.  There's a link to it 
on the front page of the K12LTSP wiki.  HTH

Petre

Liam Marshall wrote:
> If I was to get permission to spend money for a clustering option, which 
> apps from my original post would you suggest to run on an appserver?
> 
>  
> 
> More importantly, how do I set up an appserver?  Pointing me to a how to 
> would be great. 
> 
>  
> 
> __________________________________________
> 
> I am Homer of Borg.  You will be assimilated.
> 
> Resistance is fut......Hmmmm....DONUTS!
> 
>  
> 
> ------------------------------------------------------------------------
> 
> *From:* k12osn-bounces at redhat.com [mailto:k12osn-bounces at redhat.com] *On 
> Behalf Of *Liam Marshall
> *Sent:* Wednesday, March 22, 2006 11:32 PM
> *To:* k12osn at redhat.com
> *Subject:* [K12OSN] Performance Issue
> 
>  
> 
> I administer a network at a K-12 school in Winnipeg Manitoba.  I also 
> teach grades 9-12 computer classes, while other teachers use the lab for 
> their classes.
> 
>  
> 
> I am currently running K12LTSP (ver 4.4.1 I believe) on a dual xeon 3.06 
> MHz computer with 4-80 Gb SATA drives configured on a megaraid-4 
> controller raid 1+0.  2 nics, and 1 is even a gigabyte nic, but all the 
> switches involved in my network are 10/100, so it is not being utilized   
> 
>  
> 
> All applications are run from this one server, except I have a stand 
> alone box that does nothing except host our school’s mail.  Currently 
> connecting 35 thin clients which run a variety of applications the most 
> important of which are StarOffice 7 applications, Firefox for 
> surfing/research/ etc, and NetBeans 3.6 IDE for java programming, and 
> KTOUCH.  Elementary classes use such things as TuxPaint, TuxType.
> 
>  
> 
> When I teach, I frequently run into situations where the kids are 
> doing/accessing the same thing at virtually the same time.  For example, 
> they might all try to start StarOffice Text at more or less the same 
> time.  Regardless of the app, near simultaneous execution of the program 
> bogs down network.  Once in, most apps perform well enough, some notable 
> ones do not, like NetBeans. (it is fine with 5-10 but a pig when 20 use 
> it at the same time.)  And at the end of any class, when 30 ish users 
> all try to log out, the log out process itself is quite slow.
> 
>  
> 
> I am looking for ways to increase speed/traffic throughput.  This is 
> what I plan to do.  Please tell me if I am on the right track.
> 
>  
> 
> Run DSL modem into a 8 port 10/100/1000 switch.
> 
> Plug a Linksys router into switch to grab the outside IP.  Plug the 
> slower 10/100 nic from the server into the Linksys router (internet is 
> limited anyway, so a gigabyte connection would be wasted, right)
> 
> Run the gigabyte nic from the server into the gigabyte switch.
> 
> Upgrade my lab switches to 10/100 ‘s but with Gigabyte backbones, which 
> I will use to connect them to the Gigabyte switch
> 
> Any expansion in the school will use switches with gigabyte backbones to 
> connect to the main, all gigabyte switch
> 
>  
> 
> I planned to do this because from my reading of this list, and others, I 
> had gathered/assumed that this would have a significant positive impact 
> on speed/throughput.  But today I talked to someone who told me that 
> this won’t help all that much because my biggest problem/bottleneck is 
> not the lack of a Gigabyte backbone, but is the hard drive 
> accessbottleneck on the server
> 
>  
> 
>  The solution I was planning above is far less expensive than say adding 
> a few more servers to do clustering.  I have the ok for the Gigabyte 
> solution, but doubt I would get the funds for the clustering option, or 
> have the space currently, to host the extra boxes.  (space is that 
> tight!) Will my plan help at all?  Or am I wasting time/money.
> 
>  
> 
> Please advice.  Advice/opinions are welcome
> 
> __________________________________________
> 
> I am Homer of Borg.  You will be assimilated.
> 
> Resistance is fut......Hmmmm....DONUTS!
> 
>  
> 
> 
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