• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 282
  • Last Modified:

Problem with Large Memory in Windows Server 2003 Enterprise

We have a production web app (ASP .NET) running in our company on multiple systems individually.. Each instance of the App is running on a Dell Poweredge 2900 Series server. We've been running it for 2 years with no issues, The system has 2 x quad core xeon processor and 8 gigs of ram, and everything ran fine. We had issues with the webapp running into the limittations of 32 bit operating systems, using up all virtual and private bytes, so we added the /3gb switch to the boot.ini to give each worker process more resources. The /pae switch is also on in the Boot.ini. Recently We added an extra 8 gigs of memory to the systems to give it a total of 16gigs of ram. Once we put the extra memory in the system, we had all kinds of problems with the web app.. We get "Error 400 Bad Request - Malformed Packet" After about 4 hours of uptime, which starts off for a few users but ends up being every user experiencing the same problem. Windows also only shows that there are 15.2 gigs of memory in the system. Once we remove the /3gb switch, We no longer have the issue of 'bad request' errors, and the system runs fine. I should also note that the server shows a full 16gigs of memory installed in windows once we remove the /3gb switch. It's very bizarre that adding the /3gb switch would cause all of these issues, but only when the server has the extra 8 gigs of memory installed.. Wondering if there's anyone out there that could shed some light on this and possibly a solution?
0
pathix
Asked:
pathix
  • 3
1 Solution
 
DCMBSCommented:
The /3gb switch contstarins the O/S to run in 1 GB of RAM and should not be used here.  It is to be used in 32 bit systems when the max memory (4GB) is installed and you need to provide as much memory as possible for Applications.  Server 2003 really needs 2 GB of RAM to run so if you have more than 4GB it does not make sense to limit the O/S to 1 GB.
0
 
DCMBSCommented:
0
 
pathixAuthor Commented:
Yes I do agree, but it doesn't explain why we could have the /3gb switch on for almost 2 years and everything's fine when we have 8 gigs of RAM in the system, but the moment we install another 8 gigs of ram, we have nothing but problems... if we remove the additional 8 gigs of ram, everything runs smoothly again..
0
 
DCMBSCommented:
I think is just that the issues associated with the /3GB switch didn't show up until more RAM was added then the issues with kernel memory were exacerbated, resources were depleted and things started falling over.  
0
 
LMiller7Commented:
The /3GB switch has some serious issues when used on a system with a large amount of RAM. This switch restricts the OS to only 1GB of virtual address space instead of the normal 2GB. Note that this is virtual address space and has nothing to do with RAM usage. When this option is used the maximum RAM that can be used will be 16GB. The constrained system address space simply cannot provide room for the translation tables required for more. That is a theoretical maximum and in practice it may be less. This appears to the case here.

Be sure that the /3GB switch is really suitable for your situation. It is often used when it is not appropriate.

These articles explain more fully what this switch does and the many implications:
http://blogs.msdn.com/oldnewthing/archive/2004/08/22/218527.aspx
http://blogs.technet.com/askperf/archive/2007/03/23/memory-management-demystifying-3gb.aspx

0

Featured Post

New feature and membership benefit!

New feature! Upgrade and increase expert visibility of your issues with Priority Questions.

  • 3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now