Microsoft Terminal Server Question

[MulLa]

Got a question about Microsoft Terminal Services & memory.

Some people at work reckons that on x32 hardware there?s absolutely no point in going above 4GB for terminal services, you get ?nothing? out of it. The higher level techs all believe that to be the case so I haven?t really argued the point but I do beg to differ. Maybe it?s not efficient to go above 4GB but it has to assist in some ways right?

Then now they?re saying on x64 hardware, there?s no point in going above 4GB because even if the OS can address more than 4GB, the applications installed on the TS server can?t address more than 4GB. What I think is that maybe individual apps can?t address more than 4GB but each user is allocated their portion of memory from the total physical memory. Thus it would benefit if you have more memory for each user?

But according to this Microsoft documentation it seemed to suggest otherwise?
http://www.microsoft.com/downloads/deta...-4BBB-9AF8-B91BBC0D2D55&displaylang=en

Any light on the matter to put my mind at ease?!

 

[dphantom]

Your techs are correct on x32 OS's and the 4GB "practical"limit. 32 bit OS's top out at 4GB because of kernal memory limitations.

Going above 4GB on 32 bit servers does little good. However, Windows 2003 Enterprise will support up to 32GB of RAM and would be used in VM type environemnts often or large DB applications. A TS environment would not be useful unless you are also virtualizing the TS servers.

64 bit OS's blow past the 4GB limitation providing 1TB of RAM. 32 bit apps though still have the same limitations and would need to be re-written to take full advantage of a 64 bit architecture. An existing 32 bit app may see some performance improvement, but I could not say how much.

 

[MulLa]

Thanks for the response.

In other words in a TS environment running 32bit apps on 64bit OS / Hardware, there's still little point in going above 4GB?

Why are MS & HP testing with 8GB of ram in a TS environment? That's what I'm confused about. Further reading is needed

 

[dphantom]

Originally posted by: MulLa
Thanks for the response.

In other words in a TS environment running 32bit apps on 64bit OS / Hardware, there's still little point in going above 4GB?

Why are MS & HP testing with 8GB of ram in a TS environment? That's what I'm confused about. Further reading is needed

Quote: "An existing 32 bit app may see some performance improvement, but I could not say how much."

I think that is why HP and MS are testing 32 bit apps in a 64 bit OS environemnt to see what kind of performance improvement there may be with additional memory.

 

[Nothinman]

Some people at work reckons that on x32 hardware there?s absolutely no point in going above 4GB for terminal services, you get ?nothing? out of it. The higher level techs all believe that to be the case so I haven?t really argued the point but I do beg to differ. Maybe it?s not efficient to go above 4GB but it has to assist in some ways right?

Right, 32-bit Windows can address up to 64G of memory depending on the version you're running. While each process will be limited to 2G of VM itself the system as a whole will still be able to use all of the memory.

Then now they?re saying on x64 hardware, there?s no point in going above 4GB because even if the OS can address more than 4GB, the applications installed on the TS server can?t address more than 4GB. What I think is that maybe individual apps can?t address more than 4GB but each user is allocated their portion of memory from the total physical memory. Thus it would benefit if you have more memory for each user?

First it's 2G, 2G of that 4G of VM is reserved for the kernel. But the only apps that really need more than 2G of VM are odd things like 3D renderers and database servers and who runs those on thier TS boxes? Actually if you're running a 64-bit OS each process might be able to go up to 4G if it's marked large address aware, I'm not 100% sure since I don't have a way to test that but I know that all 32-bit Linux processes are allowed access to the full 4G if the kernel is 64-bit.

In other words in a TS environment running 32bit apps on 64bit OS / Hardware, there's still little point in going above 4GB?

Not if you plan on actually using the memory. But you have to realize that a lot of the memory used will be shared, i.e. if there are 10 copies of MS Word running on your TS box there's only one copy of the msword.exe binary in memory. Each user's documents will be private of course, but the binary and it's shared libraries will all be shared and only in memory once.

 

[Rilex]

If you go 64bit (and your applications are 64bit), plan on a 100% memory increase (this is per MSFT recommendations) per application/session. E.g. a standard session that took up 30MB will now take 60 on 64bit hardware.

But again, you get better access/performance when shooting above 4GB. It depends on your applications and how many users the TS will support.

 

[Nothinman]

If you go 64bit (and your applications are 64bit), plan on a 100% memory increase (this is per MSFT recommendations) per application/session. E.g. a standard session that took up 30MB will now take 60 on 64bit hardware.

I know 64-bit binaries are larger than 32-bit ones, but double? That seems like a pretty heavy recommendation.

 

[MulLa]

Thanks all for the very informative post!

Right, 32-bit Windows can address up to 64G of memory depending on the version you're running. While each process will be limited to 2G of VM itself the system as a whole will still be able to use all of the memory.

In other words, if have have "enough" multiple different processes running on the TS in 32bit, greater than 4GB can be helpful? I guess the same logic applies to 64bit OS with 32bit Apps, we need enough different processes running to make use of any memory above 4GB. Am I right to summarise it this way?

Another question. Would you guys put in a second TS server instead of scaling up a TS server to greater than 4GB?

 

[Nothinman]

Am I right to summarise it this way?

Yes, each individual process will be limited to 2G (3G with some hacks) but the whole of the system can easily use 64G with enough processes.

 

[MulLa]

Thanks Nothinman, answered all my queries!!! Can sleep in peace tonight

 

[Nothinman]

One other thing to consider is that going over 4G on a 32-bit OS requires enabling of PAE which is a slight performance hit, I would be surprised if anyone actually noticed the difference though.

 

[dphantom]

This is what I would consider the definitive word on 4Gb and 32 bit OS's

Link

As nothinman points out, PAE switch is the key.