Initializing The Replicas For Multi-Master Replication; Preventing Monopolization Of The Consumer In Multi-Master Replication - Netscape DIRECTORY SERVER 6.2 - ADMINISTRATOR Administrator's Manual

When you have configured the servers holding the read-write replicas, the
necessary replication agreements, and the servers holding the read-only replicas,
you are ready to initialize replication. You can perform this task when you create
the replication agreements on the supplier servers, or at any time afterwards. For
information on the order and procedure for initializing read-only replicas, refer
to"Initializing the Replicas for Multi-Master Replication" on page 311, and
"Initializing Consumers" on page 326.
During this operation, do not try to reinitialize the servers. For example, do not
initialize Server M1 from Server M2 if you have already initialized Server M2 from
Server M1.

Initializing the Replicas for Multi-Master Replication

In the case of multi-master replication, you should initialize replicas in the
following order:
Ensure one master has the complete set of data to replicate. Use this master to
1.
initialize the replica on the other master in the multi-master replication set.
Initialize the replicas on the consumer servers from any one of the two masters.
2.
For information on initializing replicas, refer to "Initializing Consumers" on page
326.
Preventing Monopolization of the Consumer in
Multi-Master Replication
One of the features of multi-master replication is that a supplier acquires exclusive
access to the consumer for the replicated area. During this time, other suppliers are
locked out of direct contact with the consumer. If a supplier attempts to acquire
access while locked out, the consumer sends back a busy response and the supplier
sleeps for several seconds before making another attempt.
A problem can arise if the locking supplier is under a heavy update load or has a
lot of pending updates in the change log. If the locking supplier finishes sending
updates and then has more pending changes to send, it will immediately attempt
to reacquire the consumer and will most likely succeed, since the other suppliers
usually will be sleeping. This can cause a single supplier to monopolize a consumer
for several hours or longer.
To address this issue, two new attributes were introduced (in the Directory Server
6.11 release):
Configuring Multi-Master Replication
Chapter 8 Managing Replication 317