On campus, user information is stored remotely in the Hesiod database. This means that whenever you look at the owner of a file (by doing a stat() in the directory or an ls command), you have to query the network to find the numeric userid to string username mapping. This is a somewhat intensive process, both to the servers and also to the network which your machine is on. Red Hat Linux includes a service called nscd, the Name Services Caching Daemon, which can cache this information. This service is automatically turned on for you by realmconfig. It is not advisable to turn this service off.

You can either turn this on using the /usr/sbin/ntsysv program or by executing the following command

# /sbin/chkconfig nscd ––level 345 on

This service is normally turned on for you the first time that realmconfig is run during the kickstart process or during the first time the newly installed machine boots. It is not a configurable option in realmconfig.