Some considerations must be taken into account for any multimaster scenario:
For tables that use auto-increment, collisions are possible if two
hosts select the same
auto-increment number. You can
reduce the effects by configuring each MySQL host with a different
auto-increment settings, changing the offset and the increment values.
For example, adding the following lines to your
auto-increment-offset = 1 auto-increment-increment = 4
In this way, the increments can be staggered on each machine and collisions are unlikely to occur.
Use row-based replication. Update your configuration file to
explicitly use row-based replication by adding the following to your
binlog-format = row
Beware of triggers. Triggers can cause problems during replication because if they are applied on the slave as well as the master you can get data corruption and invalid data. Tungsten Clustering cannot prevent triggers from executing on a slave, and in a multimaster topology there is no sensible way to disable triggers. Instead, check at the trigger level whether you are executing on a master or slave. For more information, see Section C.3.1, “Triggers”.