IIS & .Net Virtual memory consumption

[zissop]

Hello

I have a strange situation with my ASP.Net applications running on Windows 2003 Server x64. As soon as they get instantiated (a visitor hits a page). the virtual memory they allocate goes to something around 5GB! I can't explain the reason. I even made a very simple page (no Web.config, no global.asax, just text output) and it behaves the same.

The applications uses 3 tier architecture with all (IIS, component, etc) running at 64 bits.

I use Process Explorer to see what is happening on the processes. The problem is critical because i can't set a virtual memory limit for each application pool on IIS. If i do that, the pool gets recycled at 1-2 minutes interval due to high virtual memory allocation.

I attach the following images:

1. Show the w3wp.exe processes and their memory allocations. Note that Private bytes & working set is too low compared with Virtual Size. The process are running for about 10 hours without being recycled (i have deactivate automatic recycling based on virtual memory size on application pools).

2. Shows that the w3wp process is a 64 bit process and the application run on it's own application pool.

3. Shows the stats about Virtual And Physical memory usage. Note that the working set is far too smaller that the allocated Virtual Memory.

4. Shows the .Net CLR Memory counters. Not many GC operations, seems too normal.

Is this happening by design? I mean if the allocated virtual memory is not critical and is automatic allocated by the 64 bits processes.

If it is not, is there a possibility that there is a config file somewhere that instructs w3wp processes to allocate so much virtual memory from the beginning?

Best regards
John

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[kenobewan]

Sounds like you need the help of a server admin. What processes are running in the background? Watch these in the task manager to get an idea of what is happening and cpu usage. Does memory usage remain high or does it spike? Does your simple page run any web services or connect to a database?

[zissop]

The CPU usage is not high, between 5-50% most of the time.

The simple page does not do anything. It is just a simple Response.Write (no web.config, no global.asax).

And what about the other processes? How they affect my application? This does not sound logical.

Of course, these 5 GB per app is only virtual.Applications run smooth even they have virtually allocated 5 x5 ~ 25GB of virtual memory.

I think it is another Microsoft miracle in memory management and handling.

[Plater]

That's a head scratcher. I've seen the aspnet worker process grow in memory usage, but never to those levels (maybe 150megs, darn session objects like to eat)


Are your extra programs that run doing garbage collection like they should?
These 64bit programs are being run a on 64bit machine right?

[zissop]

These are some 64 bits components, they do not allocate so much memory. If they allocated the memory, the applications would crash the system in a few seconds.

These WEB applications run for days without allocate more that a couple of hundrend MBs each at the worst case.

That's why i setup a response.Write application to see it's behavior. No components, no allocation, now web.config, nothing. And again this app allocates 5GB virtual memory as soon i hit the aspx page.

I assume it is has to be something on a configuration file that it is machine wide (maybe machine.config - i checked it but nothing found) or a false alarm by the 64 bit Windows 2003 OS.

[zissop]

Also, as you can see on image 1, SQL Server process allocates 3,5GB of virtual memory. So is it something related to false memory indication?

[kenobewan]

The CPU usage is not high, between 5-50% most of the time.

The simple page does not do anything. It is just a simple Response.Write (no web.config, no global.asax).

And what about the other processes? How they affect my application? This does not sound logical.

Of course, these 5 GB per app is only virtual.Applications run smooth even they have virtually allocated 5 x5 ~ 25GB of virtual memory.

I think it is another Microsoft miracle in memory management and handling.

The logic behind monitoring other processes is to check the health of the server. If it is a MS problem why are posting your problem on a forum and not contacting them for support?