OSF DCE Administration Guide--Core Components

OSF DCE Administration Guide—Core Components
• You want to locate a master replica closer to where the majority of updates to the
directory originate.
To designate a new master replica, you use the cdscp set directory to new epoch
command.
Figure 21-1 illustrates an example replica set. This replica set of the /.:/eng directory
consists of three replicas: the master replica, which is stored in clearinghouse
/.:/NY1_CH, a read-only replica stored in clearinghouse /.:/NY2_CH, and a read-only
replica stored in clearinghouse /.:/Chicago1_CH.
Figure 21-1. Example Replica Set
Read−only
/.:/Chicago1_CH
Read −only
/.:/NY2_CH
Master
/.:/NY1_CH
The following command designates the read-only replica that is stored in clearinghouse
/.:/Chicago1_CH as the directory’s new master replica, designates the former master
replica (stored in clearinghouse /.:/NY1_CH) as a read-only replica, and leaves the
read-only replica stored in clearinghouse /.:/NY2_CH as it is:
cdscp> set directory /.:/eng to new epoch master \
> /.:/Chicago1_CH readonly /.:/NY1_CH /.:/NY2_CH
Figure 21-2 shows the result of the preceding command.
Figure 21-2. Example Replica Set After Master Redesignation
/.:/Chicago1_CH
Read −only
/.:/NY2_CH
Master
/.:/NY1_CH
Read −only
21.2.4 Excluding a Replica from a Replica Set
You can temporarily exclude a replica from its replica set when the clearinghouse in
which the replica is stored unexpectedly becomes unavailable. This makes it possible
for CDS to complete skulks of the directory during the time the excluded replica is
unavailable.
21 − 6 Tandem Computers Incorporated 124243