Apple Server Diagnostics - Manual (Page 28)

2 Enter the following:
sudo systemsetup -setkernelbootarchitecture x86_64
If you’re asked to authenticate, authenticate as a user with administrator privileges.
Temporarily Starting Up Mac OS X Server in 32-Bit Mode
You can override the default configuration and start up Mac OS X Server in 32-bit
mode. The server reverts to 64-bit mode the next time you restart it.
To start up Mac OS X Server in 32-bit mode:
1 Use System Preferences to start up from the volume with Server Diagnostics Mac OS X
installed.
For information, see “Changing the Startup Disk in System Preferences” on page 22.
2 While the computer is starting up, hold down the 3 and 2 keys.
28 Chapter 3 Starting Up Server Diagnostics