The automatic restart options are:
ÂÂ Restart automatically after a power failure. The power management unit automatically starts up the server after a power failure.
ÂÂ Restart automatically if the computer freezes. The power management unit automatically starts up the server after the server stops responding, has a kernel panic, or freezes.
When you select the option to restart after a freeze, Mac OS X Server spawns the watchdogtimerd daemon, which every 30 seconds commands your computer to restart after 5 minutes.
Each time the command is sent, the restart timer is reset. Thus, the timer won’t reach 5 minutes as long as the server is running. If the computer freezes, the power management unit restarts it after 5 minutes.
To enable automatic restart:
1Log in to the server as an administrator.
2Open System Preferences and click Energy Saver.
3Select restart options.
4Close System Preferences.
Ensuring Proper Operational Conditions
One factor that can cause your servers to malfunction is overheating. This is especially a problem when you cluster computers in a small space. Other factors such as humidity and power surges can also adversely impact your server.
To protect your servers, make sure you house them in a place where you can control these factors and provide ideal operating conditions. Check the electrical and environmental requirements for your systems to find what these conditions are.
In addition, make sure the facility you deploy your server has a fire alarm, and prepare a contingency plan to deal with this risk.
Providing Open Directory Replication
If you plan to provide Open Directory services, consider creating replicas of your Open Directory master. If the master server fails, client computers can access the replica.
162
Chapter 7 Ongoing System Management
