A small LTSP network setup [client specs]

[Alkis Georgopoulos]

Στις 14/06/2012 09:00 πμ, ο/η theo.schmidt at wilhelmtux.ch έγραψε:
> Am 12.06.2012 17:39, schrieb David Groos:
> ...
>> If your clients are beefy enough then I would go with fat clients. If
>> they are so-so I would go with localapps and if they are marginal I
>> would go with thin clients.
>>
>> beefy > P4 2.4 GHz with 1 gig RAM
>> so-so > P4 1.6 GHz with 512 MB RAM
>> marginal > P3 or even P2 I have heard.
>>
>> [All Edubuntu users: would you give the same cut-off points? What should
>> we publish as our recommendations?]
>
> I think these specs are too high for thin clients.
>
> I have never used fat clients, but for thin clients you can still use
> just about anything down to P1 and less - without 3D stuff (e.g. Google
> Earth, Neverball, Penguin Planet Racer).
>
> I still use thin clients with a AMD Geode 500 MHz CPU and 256 MB RAM.
> These work with screens up to 1600x1200 pixels. On a 100Mb/s network,
> this is enough to watch small videos, but not full screen. They are good
> enough for most things but marginal with large documents. E.g. large
> PDFs with hi-res pictures or very long web pages with hundreds of
> pictures will cause the client system to freeze occasionally. One of our
> thin clients has 512 MB RAM and here these problems almost never occur.
> Enabling Network-Swap helps a lot.
>
> Cheers, Theo Schmidt
>

@David: I'd go with similar specs like the ones you described, yeah:
  * Ultra thin: 128-256 RAM
  * Descent thin: 256+
  * Descent fat: 1 Gb+

@Theo: LTSP fat clients have the same performance as if they were booted 
from local disk. So they do need to be beefy.

Cons:
  * Central point of failure.
  * A small learning curve to learn about how LTSP does things.
  * Gigabit network at least from the server to the switch is required 
for thin clients, and suggested for fats.

Pros of LTSP in general:
  * Centralized user accounts, user homes (and shared folders which are 
very useful for classrooms).
  * Centralized configuration, just one lts.conf.
  * Easy to add and remove clients; nothing gets installed locally.
  * Way easier to maintain; the sysadmin only maintains the server.

Pros of fats over thins:
  * Require much less bandwidth. Watching a full HD video requires more 
than 1 Gbps on thins and just a few Mbps on fats.
  * Can do 3D, so they don't have problems with Unity-3d or Gnome-shell 
or kwin etc. And they won't have any problems in the future either, no 
matter what happens with the fancy composition WMs and wayland etc etc
  * If the clients are beefy, the applications responsiveness is much 
better than on thins. You can watch impress presentations and scroll web 
browsers and calc normally without lags.
  * They don't require any server CPU or RAM, so you can boot many fat 
clients from a modest server (e.g. a 300€ laptop).

Cheers,
Alkis