chuckp2010
asked on
64bit memory and VM question
Hello
Our environment is ESX 3.5, Windows 2003 SP2 Enterprise servers guests.
We have an application running on a VM guest. It is a 32bit app, but we have assigned 4GB RAM just in case. We figure that if the RAM is not used, we are not actually losing anything, since we are not directly paying for its exclusive use like we would do with a physical box.
We're now in the midst of a refresh, and we're upgrading to Windows 2008 R2 servers which are all 64bit OS.
I'm trying to work out what amount of RAM to assign the guests that will host the application.
- Should we continue to assign 4GB
- Is there any benefit of assigning more than 4GB for a 32bit app (I read on EE that 32bit apps could only see 4GB virtual address space per process, but I guess there could be multiple processes)
- The third option I'm thinking is using Perfmon to baseline our existing servers and find an average of memory use over, say, 48 hours. Does anyone know what the best counter to use would be and is it simply a case of running Perfmon for 48 hours and using the average value for whatever counter? Question is, does 2008 handle memory in any differernt way than 2003 server?
Our environment is ESX 3.5, Windows 2003 SP2 Enterprise servers guests.
We have an application running on a VM guest. It is a 32bit app, but we have assigned 4GB RAM just in case. We figure that if the RAM is not used, we are not actually losing anything, since we are not directly paying for its exclusive use like we would do with a physical box.
We're now in the midst of a refresh, and we're upgrading to Windows 2008 R2 servers which are all 64bit OS.
I'm trying to work out what amount of RAM to assign the guests that will host the application.
- Should we continue to assign 4GB
- Is there any benefit of assigning more than 4GB for a 32bit app (I read on EE that 32bit apps could only see 4GB virtual address space per process, but I guess there could be multiple processes)
- The third option I'm thinking is using Perfmon to baseline our existing servers and find an average of memory use over, say, 48 hours. Does anyone know what the best counter to use would be and is it simply a case of running Perfmon for 48 hours and using the average value for whatever counter? Question is, does 2008 handle memory in any differernt way than 2003 server?
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Adrian Cantrill
and good counters to use are working set, and private bytes - over time.
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
> For 32 bit applications, 4 GB memory is more than sufficient as applicaions are not designed to make use of more than 4 GB memory
Isn't it that each process can use only up to 4GB? Each app could technically have multiple processes and therefore need to use more than 4GB RAM?
Isn't it that each process can use only up to 4GB? Each app could technically have multiple processes and therefore need to use more than 4GB RAM?
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
Hi Olemo
The VM guest is 64 bit....
> An application and a process is identical
An application can (and I thought they normally do) have more than one process though? And the 2 GB limit with 32 bit OS limit is per process isn't it?
The VM guest is 64 bit....
> An application and a process is identical
An application can (and I thought they normally do) have more than one process though? And the 2 GB limit with 32 bit OS limit is per process isn't it?
As I have stated already, an application does not consist of more than one process. The process concept of e.g. UNIX does not apply here, since you can't spawn a separate process from the main process by copying itself. If you see the same .exe running more than once, they are are all separate instances (= applications = processes = files). For communication between them they need to implement own inter-process communication methods.
I don't know why you think an application might consist of more than one process.
I don't know why you think an application might consist of more than one process.