Active Directory server has less than 1 GB of memory but has the /3GB and /USERVA=3030 switches set in the Boot.ini file

Topic Last Modified: 2005-11-17

The Microsoft® Exchange Server Analyzer Tool queries two Microsoft Windows® Management Instrumentation (WMI) classes to determine the amount of physical memory in the Active Directory® directory server, and the amount of virtual address space allocated to user mode processes. The table describes the classes and keys being evaluated by the Exchange Server Analyzer.

Class	Key	Description
Win32_OperatingSystem	MaxProcessMemorySize	Maximum number of kilobytes of memory that can be allocated to a process.
Win32_OperatingSystem	OSProductSuite	Installed and licensed system product additions to the operating system.
Win32_ComputerSystem	TotalPhysicalMemory	Amount of random access memory (RAM) installed in the computer.

If Exchange Server Analyzer determines that the directory server has less than 950 MB of RAM, and that the value for the MaxProcessMemorySize is more than 2097024 but less than 3104640, a warning is displayed.

This warning indicates that the directory server is not correctly configured for optimal memory usage in two respects:

The /USERVA=3030 startup switch has been set. This switch is only required on Exchange Server computers with 1 GB or more of memory that are running on a Microsoft Windows Server™ 2003 operating system.
The /3GB startup switch has been set. This switch should only be used on Exchange servers with 1 GB or more of memory that are running any of the following operating systems:
- Microsoft Windows Server 2003 Standard Edition
- Microsoft Windows Server 2003 Enterprise Edition
- Microsoft Windows Server 2003 Datacenter Edition
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Datacenter Server

Important:
The /3GB switch should not be used on Windows 2000 Server because it is unsupported and can cause application or operating system crashes. Furthermore, the /3GB switch is only supported on the above operating systems when 1 GB or more of physical memory is installed.

If you encounter this warning on a system in which 1 GB of physical memory is installed, it could indicate that another component, such as a video card, has been allocated some of this physical memory at the hardware level, thereby making the allocated physical memory unavailable to the operating system. In these cases, the amount of memory installed physically according to Windows will be less than the actual amount of physical memory installed in the computer. If you encounter this situation, you should compare the amount of installed memory reported by the BIOS with the amount of installed memory reported by Windows.

To correct this warning on Windows Server 2003

Right-click My Computer and select Properties. The System Properties dialog box appears.
Click Advanced.
In the Startup and Recovery area, click Settings. The Startup and Recovery dialog box appears.
In the System startup area, click Edit. This will open the Windows Boot.ini file in Notepad.
In the [Operating Systems] section, delete the following switches from all startup lines: /3GB /USERVA=3030
Save the changes and close Notepad.
Click OK twice to close the open dialog boxes, and then restart the computer for the change to take effect.

To correct this warning on Windows 2000 Server

In Windows Explorer, locate the system partition.
If you cannot see the Boot.ini file, it could be because the Folder Options are set to Hide protected operating system files. If this is the case, in Explorer, click Tools, Folder Options, and then click the View tab. Clear the Hide protected operating system files (Recommended) check box. When prompted with the warning box, click Yes.
As soon as the Boot.ini file is visible in Explorer, right-click the file, click Open With, and click Notepad to open the file.
In the [Operating Systems] section, delete the following switches from all startup lines: /3GB /USERVA=3030
Save the changes and close Notepad.
Restart the computer for the change to take effect.

For additional details about how to use the /3GB and /USERVA startup switches, see the following Microsoft Knowledge Base articles:

308356, "Memory usage by the Lsass.exe process on domain controllers that are running Windows Server 2003 or Windows 2000 Server" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=308356)
297812, "How to Use the 4GT RAM Tuning Feature" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=297812)
311901, "The effects of 4GT tuning on system Page Table Entries" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=311901)
316739, "How to Use the /USERVA Switch in the Boot.ini File to Tune /3GB Configurations" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=316739)
325044, "HOW TO: Troubleshoot Virtual Memory Fragmentation in Exchange 2003 and Exchange 2000" (http://go.microsoft.com/fwlink/?LinkId=3052&kbid=325044)
815372, "How to Optimize Memory Usage in Exchange Server 2003" (http://go.microsoft.com/fwlink/?LinkId=3052&kbid=815372)