Using Operating System Backups

Because a namespace is a distributed database to which modifications are synchronized at variable intervals, any traditional backup of a particular server system always contains old and incomplete information. If you frequently create, modify, or delete names, restoring an out-of-date backup can cause recently created names to disappear, recent modifications to be reversed, or recently deleted names to reappear in the namespace. The degree to which a traditional backup reflects the current condition of a clearinghouse depends entirely on the following conditions:

· How recently the backup was created

· What modifications were made since that time

· Whether the backup included the clearinghouse files in the directory dcelocal/var/directory/cds

If you decide to use operating system backups, you only need to back up the server systems whose clearinghouses store master replicas of directories. To ensure that you backup your namespace completely, check for the following:

· The servers on these systems are disabled by using the dcecp cds disable command

· The files in the root directory dcelocal/var/directory/cds are included in the backup

If your namespace is small enough to be maintained in one clearinghouse, you can reliably use traditional operating system backups to save and restore the clearinghouse data. If only one clearinghouse exists, only one replica (the master replica) of each directory exists. This eliminates the need to account for the discrepancies that may exist among multiple directory replicas. Remember that the more frequently you back up clearinghouse data, the more up-to-date that information will be if you need to restore it.