OSF DCE Administration Guide--Core Components

Restructuring a Namespace
21.2.1 Before You Modify a Replica Set
Before you modify a directory’s replica set, you need to know how many replicas exist,
their replica types, and the name of the clearinghouse where each of the replicas is
stored. The command that you use to modify a directory’s replica set does not allow you
to accidentally leave a replica out of the new set. You must explicitly list all existing
replicas that are in the set. You can include or exclude any replica from the new set, but
you must account for all replicas. Only one of the replicas that you include in the new
set can be designated as the master replica.
To display the names of all of a directory’s replicas, use the dcecp directory show
command. This command queries the directory’s CDS_Replicas attribute to gather this
information. (See Chapter 18 for information on how to use the dcecp directory show
command.)
21.2.2 Permissions Required for Modifying a Replica Set
The permissions for modifying a directory’s replica set are as follows:
• You must have administer permission to the directory. Also, the server principal
needs administer, read, and write permissions to the directory.
• When designating a new master replica, you also need write permission to the
clearinghouse that stores the current master replica. The server principal needs write
permission to the clearinghouse that stores the read-only replica that you intend to
designate as the new master replica.
The server principal on the server where the new master replica will be located
needs administer, read, and write permissions to the directory.
When you know which replicas to include and exclude and have changed permissions
that need to be changed, issue the set directory to new epoch command to modify a
directory’s replica set. Instructions for your two options—designating a new master
replica, and excluding an existing read-only replica—are given in the sections that
follow.
21.2.3 Designating a New Master Replica
Sometimes, for configuration management reasons, you may want to designate a
different replica as a directory’s master replica.
For example, you can specify a new master replica when
• A server system whose clearinghouse contains one or more master replicas will be
down for an extended period of time or removed permanently from the network.
• A clearinghouse that stores one or more master replicas will be deleted from the
namespace.
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