When the Number of hosts is large, the use of server groups can simplify the topology and improve resource usage. In a topology with 16 masters, the use of four server groups, each containing four masters, is easier to manage than 16 fully meshed masters.
Setting up a such a topology involves the following steps:
Configure the 16 masters, without any replication agreements.
Create four server groups and include four masters in each group.
Set up replication agreements between all the masters in a single group.
Set up replication agreements between the first master of each group, the second master of each group, and so forth.
The following figure shows the resulting topology.