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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 perform the procedure in this topic, consider the following:
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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.
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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.
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Right-click My Computer and select Properties. The System Properties dialog box will appear.
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Click the Advanced tab.
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In the Startup and Recovery area, click Settings. The Startup and Recovery dialog box will appear.
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In the System startup area, click Edit. This will open the Windows boot.ini file in Notepad.
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In the [Operating Systems] section, add the following switches to the end of the startup line that includes the /fastdetect switch: /USERVA=3030
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Save the changes and close Notepad.
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Click OK two times to close the open dialog boxes, and then restart the computer for the change to take effect.
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For more information about the /3GB and /USERVA startup switches, see Optimizing Memory Usage in Exchange Server 2003.
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For more information about optimizing Exchange Server memory usage and performance, see the following Microsoft Knowledge Base articles:
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"Exchange 2000 requires /3GB switch with more than 1 gigabyte of physical RAM" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=266096).
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"HOW TO: Troubleshoot Virtual Memory Fragmentation in Exchange 2003 and Exchange 2000" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=325044).
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"How to Optimize Memory Usage in Exchange Server 2003" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=815372).
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"XADM: Using the /Userva Switch on Windows Server 2003-Based Exchange Servers" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=810371).
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"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).
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"Overview of Dependencies and Requirements for Exchange Server 2003 Features" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=822178).
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"Exchange 2000 requires /3GB switch with more than 1 gigabyte of physical RAM" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=266096).
