Terminal Server >4GB RAM

I'm drawing up a spec for a terminal server. I'm looking for advice on how to address the memory requirements. There will only initially be 30 odd clients, but I want to spec for more. I initially considered using 8GB RAM, with 32 bit Advanced 2003 with PAE. But having read about some issues with TS and PAE, this may not be suitable..? What are others running? Would you recommend 32 bit with, or without PAE, or just go for 64 bit? Is 64 bit likely to introduce lots of compatibility issues on top of those usually associated with TS, or will most 32 bit apps run in compatibility mode?

cheers
Mike

Would it not be better to have two servers with 4GB RAM each. By doing this you would add some redundancy.

It would, but adding more memory is cheaper than an additional server. This is really a pilot to see whether thin client is suitable for other areas in the school (in terms of performance). I accept your point about redundnacy, and I would add more servers if I were to start installing a significant number of additional clients. Thanks

@Ric_

That makes more sense to me.

The real limit is the Kernel memory. In a system with 8GB running with the PAE switch, each user is still presented with 4GB of virtual memory (2GB for the applications and 2GB of shared kernel space). The users all share the 2GB of kernel space, thus it is the limiting factor. Adding more memory to the machine would provide more memory for the memory subsystem to address and utilize when the users' applications wish to place data into memory, thus the additional memory would help performance of the memory subsystem to a point in that it does allow more information to be kept in RAM rather than on the pagefile, but the users would still only have 2GB of memory addresses for use for their applications. The memory addresses given to the users will not change (this is the 4GB limit caused by 32-bit apps) regardless of how much physical RAM in the system.

So, short and sweet, more physical memory will help to a point in that it gives the memory subsystem more memory to store application data, but it does not overcome the 2GB shared memory limit, nor does it provide more than 2GB of memory addresses to the users. Additionally, the 3GB switch would only worsen the matter by cutting the amount of shared kernel memory in half.

Additionally, PAE support must be enabled in the application for it to function. If it does not, then your back to the above situation. Worse still, PAE uses double the amount of kernel memory vs normal memory allocation. Thus you actually cut your Terminal Servers capacity in half.

In conclusion, if you must use 32bit apps. Use 4Gb with no /PAE and no /3Gb. Otherwise upgrade to 64bit.

Thanks Geoff!

So, if I were to use 32-bit applications on 64-bit Windows, would I still come up against the memory limitations of 32-bit?

@meastaugh1: You will not come up against the memory problem in 64-bit Windows and 64-bit is supposed to be REALLY nice for terminal servers. However, older software titles (also known as everything that you will find in a school)will tend to break when trying to run on a 64-bit OS. 16-bit apps will not run at all!

As Ric said, you wont. However your software is unlikely to run.

Thanks both for your advice.

We deploy large scale thin client system in schools.

We always go for 4 GB boxes to run 30ish sessions. If you need more, add more tin. An 8GB box will not run double what a 4GB box does.

In a school environment you are more likely to become proc bound than you are memory bound.

I have a school in Herts running around 130 thin clients on Sun Ray. You are more than welcome to come and have a look.