Maximum users on a server

[cybercop23]

Hi all.

Is there a maximum number of users that can be connected at one time to a Citrix server? Or is it a matter of server horse power.

We have three 4 way processing servers with 5GB MEM each, in a farm with load balancing. Each server can currently handle 75 concurent users at 60% CPU, so we have a total of 225 accross 3 servers in one farm. Is there really room for grouth or CItrix can't support more then 75 users per server?

Thanks for your help

 

[terrywilson]

How long is a piece of string...

75 users per server is pretty good (depending of course upon the amount of apps each runs). We had a network problem once which made all of our servers unavalable but one; it got 140 users on it before it fell over; it ran slow as hell and was out of memory so paging furiously but it just frozen at 150.

Our typical user runs Notes, three client access sessions, an office app and a custom app.

We were running about 50 users per server (Dual P3 1.11 / 2ghz RAM) and the performance counters weren't really showing any problmes (paging, cpu queue etc) but it would do strange things. We have since added more servers to bring them down to about 30 per server and it all seems quite well behaved.

On the citrix site or on thin.net there is an interesting article comparing performance between 2 and 4 way boxes; well worth the read. I can't think of the name, but it I found it only a month or two ago so won't be too buried.

 

[ascotta]

It is really a matter of oomph (technical term)

Its more a processor thing you could realistically say 20 users per processor, but it really does depend on the apps they are running. You have 225 users divided by 20 = 15 - 16 processors of which you have 12. I would say you are a machine light. However should one of these machines die you are then trying to get 225 users on to 8 processors or 12 if you upped the machine count.

You are probably 8 proessors short. My suggestion would be to put in duals (eggs in one basket theory) therfore 4 new dual boxes this may add a bit of complexity via load management but give you far better redundnacy.



Cheers
Scott

 

[rayzze]

Terry Wilson is correct, the two way processors scale much better then the 4 way. Citrix scales pretty linearly up to two processors on Windows 2000, but dramatically curves on 4. Windows Server 2003 is supposed to scale well up to 4 processors, but then you may need to purchase TS cals (Microsofts new licensing model...) which can be costly. It really depends on the speed of those 4 processors also. The logic of users per processor is a sliding scale because if you 4 processors are 900 MHZ, another server with (2) 3.06 gig processors will be able to handle many more users if both have the same amount of ram.

Hope this helps,