Replication

Replication can degrade performance in the following situations:

When the master replica, in a master–slave replication, only allows write requests. Password Services usually requires updates to the password blob attribute for each authentication. If only the master replica can process writes, then each write request is redirected to the master.
The redirection results in additional time spent on the authentication step, and the master-replica may not be able to accommodate the rate at which writes occur.
When LDAP referrals are enabled. LDAP referrals can degrade performance because each request may involve more than one request to a directory.