How to Set the /USERVA Startup Switch in Windows

Topic Last Modified: 2005-05-10

Windows Server 2003 includes support for two boot.ini startup switches—/3GB and /USERVA—that enable you to tune the allocation of use of memory and memory address space.

This topic explains how to set the /USERVA startup switch in Windows Server. For detailed steps about how to set the /3GB startup switch, see How to Set the /3GB Startup Switch in Windows.

Before You Begin

Before you perform the procedure in this topic, consider the following:

The /USERVA switch should be used only for applications that support it, such as Exchange Server 2003, and with the specific values supported by those applications.
When used on Exchange Server 2003 systems, /USERVA should always equal 3030 (e.g., /USERVA=3030). This value causes an additional 40 MB to be allocated to the operating system, and enables you to add more users without consuming all available system resources.

Procedure

To Set the /USERVA Startup Switch in Windows

Right-click My Computer and select Properties. The System Properties dialog box will appear.
Click the Advanced tab.
In the Startup and Recovery area, click Settings. The Startup and Recovery dialog box will appear.
In the System startup area, click Edit. This will open the Windows boot.ini file in Notepad.
In the [Operating Systems] section, add the following switches to the end of the startup line that includes the /fastdetect switch: /USERVA=3030
Save the changes and close Notepad.
Click OK two times to close the open dialog boxes, and then restart the computer for the change to take effect.

For More InformationReference

For more information about the /3GB and /USERVA startup switches, see Optimizing Memory Usage in Exchange Server 2003.
For more information about optimizing Exchange Server memory usage and performance, see the following Microsoft Knowledge Base articles:
- "Exchange 2000 requires /3GB switch with more than 1 gigabyte of physical RAM" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=266096).
- "HOW TO: Troubleshoot Virtual Memory Fragmentation in Exchange 2003 and Exchange 2000" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=325044).
- "How to Optimize Memory Usage in Exchange Server 2003" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=815372).
- "XADM: Using the /Userva Switch on Windows Server 2003-Based Exchange Servers" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=810371).
- "You Must Use the /3GB Switch When You Install Exchange Server 2003 on a Windows Server 2003-Based System" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=823440).
- "Overview of Dependencies and Requirements for Exchange Server 2003 Features" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=822178).