Citrix PS / Xen App 4.5 – Put new servers onto VMs or Dedi

LukeQuake

I’m weighing up the options between adding further Citrix PS / XenApp 4.5 servers to our farm into Virtual Machines (using VMWare or XenServer) or whether it would be better to just buy a physical box per server. As technically the users’ are already being virtualised anyway, it’s just the OS that isn’t.

We tend to get approximately 20-30 users per Quad Core, 4GB Ram, Win 2k3 Standard box, but would obviously have to invest in much beefier hardware if we want to vitalise 2-3 servers onto a single piece of hardware. In addition the hardware would effectively become a single point of a failure for all of the additional PS/Xen App servers that we got from this virtual environment, unless we looked at investing potentially a lot more money into additional redundant boxes and using Marathon VM or the VMWare alternative to protect them. With the physical boxes, I can simply separate them between sites and if one goes, my other servers should still be running and able to take the load of the users’ whilst we carry out repairs.

What in your opinions would be the best course of action?

Thanks in advance.

Regards,

Luke

astorrs

The biggest question - what is stopping you from going above 20-30 users per server right now? CPU or memory?

LukeQuake

memory...

astorrs

Then go for it. But you'll need to crank up the memory (for 4 cores per server you'll want to look at 32GB RAM). You can expect to get less users per virtual Citrix server, but more Citrix servers per physical server...

So while you might go down to 15-20 users per virtual server, you may get something like a total of 120-160 users per physical server. Do you have an existing virtualization investment in Citrix XenServer or VMware ESX? If these are going to be new servers and you're planning on using one of those two hypervisors you would be smart to use AMD Quad core processors, their support for RVI (nested page tables) will really help with the high number of context switches present on terminal servers.

LukeQuake

Thanks astorrs, you've got me thinking!

We currently don't use XenServer or VMWare ESX. I was thinking about the XenServer hypervisor just because I'd like to keep Citrix with Citrix.

The servers I'd be putting it on are running duel Intel Xeon Quad cores, but also look at new servers. I'll have a play around with the Xen hypervisor tomorrow if I get chance, it's free isn't it? - I'm also presuming that you can specify say a certain number of cores per virtual environment and I'll also need a Windows Server 2003 license per VM to put this into production?

Regards,

Luke

astorrs

Maybe I should ask a basic question

How many Citrix Presentation Servers are we talking about here?

LukeQuake

astorrs,

2 currently looking to expand to 4-5 over the next 12 months.

Apologies if I didn't make myself clear.