Thin Clients

[Mark Haney]

Rashkae wrote:
> Wade Smart wrote:
>> 20081007 1112 GMT-6
>>
>> A school system local to me asked about the possibility of moving to 
>> linux. Of course I talked that up right away. But then this older bloke 
>> asked about setting up Thin Clients at each school and linking the 
>> server from each school to the main server. I thought about it (on the 
>> spot of course) and while it sounds good in theory, I personally dont 
>> know if that would work OR if the overall benefits pan out.
>>
> 
> It works really well and the benefits are great.

This I do agree with.  When you have a well designed system with lots of 
leeway for those sudden spikes.

> 
> Now, to run full desktop environments, you will need more than a few
> application servers.  If using commodity hardware (as opposed to dual
> Xeon with over 20GB of ram), You'll probably only want 10 to 20 clients
> per application server.

Again, agreed.  However, you can put more clients on the newer hardware, 
even commodity, as long as you think of a basic metric I've used before. 
  each user will consume approximately 10% CPU and about 300-1000MB RAM 
(RAM is the biggest unknown most of the time, better to over guess than 
under).  Most thin clients will be on the bottom end of that, but like 
anything the more RAM you have the better.  I would be willing you bet 
you could get 40-50 clients on a dual core with 10+GB RAM, although a 
quad core would obviously have more 'give' to it.

> 
> It becomes impractical to use removable media on the clients, so clients
> that need to access removable media might not be appropriate for this setup.

I don't know so much about this.  I can see the idea behind it, but I'm 
not sure I completely agree.  Teachers do so much work at home, having a 
flash drive is handy for transferring documents.  I suppose you could 
make the thin client desktop available over the internet to the 
teacher's home, but that might not be an option.

> 
> The benefits are being able to use any old computer as a thin
> client....even on the desk I type this, I'm running a full Gutsy Gnome
> Desktop from my client, which is the oldest pc in the office, a PII 350Mhz

Yeah, this is obviously the biggest gain here.  Schools are always 
behind the adoption curve with computers.  This is the best kind of 
recycling.

> 
> Latency is absolutely not noticeable for regular office applications,
> web browsing and audio.  I can even watch small size movies without
> issue.  (latency becomes problematic for videos over 500x500, and
> obviously, you wouldn't be able to play videos on more than 1 or 2
> clients simultaneously)
> 

This is true if the traffic is mostly LAN based.  Having the majority of 
the traffic come from the CO for the thin clients worries me.  If the 
terminal server is at the school this is a no-brainer.  At the CO, a LOT 
depends on the districts infrastructure.  In a relatively small district 
(or well funded) this shouldn't be a huge problem.  Again, this is the 
big unknown for us, we don't know the school district at all, so I'm 
completely guessing here.  A good solid fiber network between schools 
should handle the load fine.  Anything else and I would have to look a 
lot closer at it before I attempted it.


> 
> 


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Mark Haney
Sr. Systems Administrator
ERC Broadband
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