OSF DCE Administration Guide--Core Components

OSF DCE Administration Guide—Core Components
3. Perform the system upgrade.
4. Restore all the files that you backed up in step 2.
5. Follow the procedure described in Section 17.6 for restarting a server. When
the server process starts, it automatically locates the appropriate restored files
and starts all clearinghouses on the system.
17.8 Backing Up Namespace Information
Because updates and skulks of directories can occur asynchronously, and because of the
distributed nature of a namespace, you cannot always depend on traditional backup
methods to preserve CDS data.
The rest of this chapter tells when to use the following backup mechanisms:
• Directory replication
• Operating system backups
17.8.1 UsingReplication to Back Up Namespace Information
Directory replication is always the most reliable way to back up the information that is in
your namespace. When you create a new replica of a directory at a clearinghouse, you
are not only distributing the information but also creating an up-to-date, real-time backup
of the information. If a replica in one clearinghouse becomes unavailable, users can look
up the information they need in another replica of the directory in some other
clearinghouse. The more replicas of a directory you create, the more likely users will
always be able to find the information that is contained in the directory somewhere in the
namespace.
If an entire clearinghouse is corrupted, you can restore it by creating a new clearinghouse
and then creating new replicas of the directories that were stored there. (See Chapter 18
for complete information on how to create a replica.)
17.8.2 UsingOperating 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restoring an out-of-date backup can cause recently created names to disappear, recent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:
17 − 6 Tandem Computers Incorporated 124243