Re: Widen LTSP uplink / Re: ltsp hardware again

[Knut Yrvin <knuty@skolelinux.no>]

Onsdag 12. august 2009, skrev RalfGesellensetter:
> I ascribe this to
> - new TFT screens with higher resolution (more X data to serve)
> - increasing use of Flash videos
> - increasing use of animations all over the web
> - possibly also more use of Java related stuff (is this rendered
>   by native X11 sequences or rather as direct graphic drawing?)

Such requirements calls for Diskless Workstation[1] (aka Low Fat 
clients). This is explained in some depth here:  

1. http://wiki.debian.org/DebianEdu/HowTo/LtspDisklessWorkstation

Technologies as X, FreeNX og Citrix (aka RDS)[2] can't really handle the 
bandwidth requirement in an efficient way when requiring Flash videos, 
more heavy graphics and animations etc. This because of network 
saturation you get inherent from the network traffic generated at the LTSP 
server(s), which has to be transported to each client PC. 

2. http://en.wikipedia.org/wiki/Terminal_Services

Going for LTSP X-clients (aka thin clients), you may end up with 5-10 
servers when supporting 100-150 clients, and a heavy duty 1 Gbit/s 
between each server and the switch serving the LTSP clients. To cost 
upgrading the network, acquiring new switches and mores servers, can 
easily be more expensive than a light upgrade of the client PC's, 
keeping the 100 Mbit/s network. 

Then it's probably better to use one single server, supporting 100-150 
Diskless Workstations (which actually runs with the LTSP solution). Then 
the graphics and video are mostly transported between local parts on 
each PC. Shuffling graphics between local memory and the graphic ship on a 
PC is easy compared to sending such individual data chunks from a server 
to many clients. 

If you go fore Diskless LTSP you should use PC's with minimum 
800-1000Mhz, 256-512MB ram and local swap disk. 

And you can keep several thin LTSP clients in your computer network 
still, doing an transition from thin clients to Diskless LTSP's when 
future investments allow it. 

In Norway whole municipalities are running Diskless workstations at all 
the schools. They say it's rock solid and are much better suited for 
Flash, video and other graphics compared with thin LTSP client's. The 
Diskless workstations is an evolution to the requirement schools expect 
of their PC's in 2009 which is quite more heavy compared to 2001, when 
Skolelinux started. 

Best regards

Knut Yrvin