Recipe 3.15 Enabling the /3GB Switch to Increase the LSASS Cache
3.15.1 Problem
You are using more than 1 GB of memory on your domain controllers
and want to enable the /3GB switch so that the LSASS process can use
more memory.
3.15.2 Solution
Edit the boot.ini file on the
domain controller to contain the /3GB switch:
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Windows Server 2003" /3GB
Restart the computer.
|
On Windows Server 2003, you can edit the boot.ini file by opening the System applet in
the Control Panel. Click the Startup and Recovery tab and click the
Edit button.
On Windows 2000, it is not so easy. You need to open an Explorer
window, select Tools Folder Options, and click the view
tab. Uncheck "Hide protected operating system files
(Recommended)," and check "Show
hidden files and folders." Now browse to the root of
your operating system partition (e.g., C:) and edit the boot.ini file with a text editor.
|
|
3.15.3 Discussion
When computers are referred to as 32 or 64-bit computers that means
they support memory addresses that are 32 or 64 bits long. This is
the total available memory (virtual and real) that can be processed
by the system. Since the days of Windows NT, Microsoft has split
memory allocation in half by giving applications up to 2 GB and the
Windows kernel 2 GB of memory to use (32 bits of address space =
2^32 = 4 GB). In many cases,
administrators would rather allocate more memory to applications than
to the kernel. For this reason, Microsoft developed the
/3GB switch to allow applications to use up to 3
GB of memory, leaving the kernel with 1 GB.
The /3GB switch is supported only on Windows 2000
Advanced Server, Windows 2000 Datacenter Server, Windows Server 2003
Enterprise Edition, and Windows Server 2003 Data Center Edition, and
should be used only if the computer has more than 1 GB of physical
memory. For a good description of how LSASS uses memory, see MS KB
308356.
3.15.4 See Also
MS KB 99743 (Purpose of the BOOT.INI File in Windows 2000 or Windows
NT), MS KB 291988 (A Description of the 4 GB RAM Tuning Feature and
the Physical Address Extension Switch), and MS KB 308356 (Memory
Usage By the Lsass.exe Process on Windows 2000-Based Domain
Controllers)
|