OSF DCE Administration Guide--Core Components

Restructuring a Namespace
To exclude a replica from a replica set, you use the cdscp set directory to new epoch
command with the exclude argument to rebuild a directory’s replica set, excluding the
replica that you specify. Remember that you must account for all existing replicas in the
command.
In the following example, the replica set of the /.:/eng directory consists of three
replicas: the master replica, which is stored in clearinghouse /.:/Chicago1_CH, and the
read-only replicas that are stored in clearinghouses /.:/NY1_CH and /.:/NY2_CH.
In this case, the /.:/NY1_CH clearinghouse is cut off from the network because of
accidental damage to the network transmission lines. Connectivity to the clearinghouse
will not be restored for several days. During this period, skulks of the /.:/eng directory
will fail unless you temporarily exclude the read-only replica that is stored in
clearinghouse /.:/NY1_CH.
To make it possible for skulks of the /.:/eng directory to succeed during the repair period,
enter the following command to overwrite the current values of the /.:/eng directory’s
CDS_Replicas attribute with new values that include only the replicas that are stored in
the /.:/NY2_CH and /.:/Chicago1_CH clearinghouses:
cdscp> set directory /.:/eng to new epoch master /.:/Chicago1_CH readonly \
> /.:/NY2_CH exclude /.:/NY1_CH
Figure 21-3 shows the result of the preceding command.
Figure 21-3. Example Replica Set After Replica Exclusion
/.:/Chicago1_CH
Read −only
/.:/NY2_CH
Master
/.:/NY1_CH
Read −only
excluded
When connectivity with the /.:/NY1_CH clearinghouse is reestablished, enter the
following command to reintroduce the read-only replica that is stored in clearinghouse
/.:/NY1_CH to the replica set:
cdscp> set directory /.:/eng to new epoch master /.:/Chicago1_CH readonly \
> /.:/NY1_CH /.:/NY2_CH
Note: Always reintroduce excluded replicas to their replica sets as soon as
possible after the clearinghouse in which they reside again becomes
available.
21.3 Deleting Directories
You may sometimes want to delete a directory from your namespace when the
information that it contains is no longer needed by users. You must take two
124243 Tandem Computers Incorporated 21−7