Which hardware?

[Knut Yrvin]

Torsdag 15 juni 2006 18:07, skrev simon.balderson at btinternet.com:
> Essentially, my question is - does anyone have experience with
> Edubuntu/LTSP for around 32 clients? Most of the examples I've seen
> online are for 10 to 15 machines. Will 4GB of RAM on the server do
> it, or will that slow things down? 

Probably 2 GB is enough. Every client in a thin client network uses 
around 64 MB of memory. The server software itself uses around 256 MB 
of memory with no clients. Because of an error in FireFox 1.5 with 
caching pictures 3 times when using tabbed browsing, you should 
probably beef up the memory pr. client to 128 MB on the server side. 

15 * 128 MB = 1920 MB 
1 * 256 MB = 256 MB 
Sum = 2,1 GB RAM ~ 2 GB RAM (on a server with 15 thin clients)

That said. We know a lot of schools that runs 60-70 thin client on one 4 
GB RAM Skolelinux/Debian-Edu server with on  a 100 Mbit/s switched 
network. The One Laptop per Child project has advised the Mozilla 
Firefox guys to clean up the memory eating bug in that browser, so it 
will probably be fixed in next main version of Firefox. 

The thin client needs at least 128 KB RAM if you run Edubuntu or 
Skolelinux 2.0 because of the "memory hungry" Muekow implementation of 
the login manager, and the lack of swap over network: 

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=367606

> It'll mainly be used for running 
> OpenOffice and firefox. Are there any servers you would recommend?

Standard Dell, Fujitsu-Siemens or HP should do. It's the memory and hard 
drive that makes the prices go up. You should consider mirrored 
SATA-disk for the server. The disks should have a 5 year warranty for 
server operation. 

> Also, is using OpenMosix with LTSP a good plan? 

No it's not if you have 2 hours a week to maintain the system. 

> I'm looking to make 
> everything as scalable and extendable as possible.

Then I would go for diskless workstations. Then you can run 150 clients 
on a server on a 100 Mbit/s switched network. Over 30 schools does that 
in Norway. This report gives some background: 

http://developer.skolelinux.no/artikler/2006-04-02-debconf6.pdf

One last thing. It's also posible to add a lot of thin client servers to 
a single file server. Some people I've talked with says that they 
support 10 thin client to a workplace PC (not a server) that costs 400 
USD. Thats the only thing they have the money to purchase. 

But 5-6 of this macines to support 50-60 thin clients cost 2400 USD. A 
nice server that support 50-60 thin clients cost almost the same. With 
one solid server you have 5 times less hard drives to support and 
update. Thats less time to suport on a higher quality server hardware. 
So the 100 USD saving of bying a lot of cheap machines could easily be 
more expensive because of the number of hard drives to maintain. 

So my experience: It's cheaper to by one server compared to many PC's as 
a server replacement :)

Regards

Knut Yrvin