Re: Administration framework of skolelinux
A dual core "server" CPU are sufficient for running 70 thin client
(X-server based) on 100 Mbit/s switched network, with 50 clients
actively in use. It's not sufficient for running flash animations with
heavy graphics or videos. You might get away with running 60 clients
turning of all the bling you got on modern Linux desktops.
It's the 100 Mbit/s network which is the bottleneck in this setup
where each client are running 1-2 Mbit/s in fully use (when not
running video which often takes 20-30 Mbit/s through an X-protocol).
To make it simple, 50 clients * 2 Mbit/s = 100 Mbit/s.
Regarding video and heavy flash graphics. It's takes milliseconds
before your'e ending up supporting only 4-5 concurrent clients. More
than that, both network and CPU are saturated with traffic and
workload. (Running Citrix, RDP or FreeNX with video or heavy graphics
are worse than the X-protocol. Microsoft experts recommends to limit
number of clients to 25-30 to a Citrix server. Video and flash are not
recommended at all in such setup.)
For running +50 concurrent client on a server, I would consider a 1
Gbit/s thin client network (you might split it from a 1 Gbit/s
backbone network to 100 Mbit/s switches with 1 Gbit/s "input" and a
100 Mbit/s "output". I'm simplifying the Internet protocol here to
explain highly advanced bandwidth calculations here, to make it with
simple multiplications). The need for dual core or quad core CPU are a
little more flexible. You can run dual core for 60 thin clients.
Since now 1Gbit/s network are available for a while, now also being
affordable. It changes the number of thin X-clients you can run on a 1
Gbit/s switched backbone thin client network. I don't know the exact
number, but 150 or even 200 thin client might supported depending on
throughput capacity on the switches (and cables). Then a 150 thin
clients setup might work. Remember then also memory consumption and
more CPU power might be required. E.g. quad core CPU and 16 GB RAM for
150 thin clients.
Of course running lowfat clients (diskless) are recommended. You can
run 150 lowfat clients on a 100 Mbit/s network. You get full video and
flash support. Such setup needs clients with +512 MB RAM and +1,5 GHz
CPU and a server with 2 GB RAM and dual (or even single core) CPU.
Also, you can run such a setup in a combination. E.g run 40 thin
client on old hardware and 20 lowfat clients for newer hardware :)
Many schools does that too :)
Beste hilsener
Knut Yrvin
--
mob: + 47 934 79 561
2014-02-05 15:17 GMT+01:00 Franklin Weng <franklin@goodhorse.idv.tw>:
> Hi Knut,
>
>
> Thanks for your detail explanation.
>
>
> For "thin client", which runs applications at server side, you just
> mentioned network bandwidth issue. However, besides network bandwidth
> issue, how many clients can a main server afford? In the "Requirement"
> document it mentioned 4GB for 50-60 clients. Will the server CPU loading
> too heavy when 60 clients run concurrently?
>
>
> Franklin
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