Hi,

I'm trying to correctly conceptualize the different replication models in OpenLDAP 2.4 and I'm a little unsure if I have my facts right.  As far as I can tell from the OpenLDAP 2.4 Administrator's Manual the following is true:

LDAP Sync Replication (a.k.a syncrepl)

- Single Master Replication

- Provides HA for reads to the directory but not for writes.

- Provides data consistency

- Replicates all attributes of the modified DN, even the unchanged ones.

Delta Sync Replication

- Single Master Replication

- Provides HA for reads to the directory but not for writes

- Provides data consistency

- Replicates only the modified attributes of the modified DN

N-Way Multi-Master Replication

- As the name suggests, Multi-Master Replication

- Provides HA for reads and writes to the directory.

- Does not provide data consistency

MirrorMode Replication

- Hybrid between SMR and MMR

- Creates chicken and egg problem with regards to HA - external frontend is a potential failure point and must also be made HA

- Provides HA for reads and writes to the directory (assuming external frontend is made HA)

- Both OpenLDAP servers can replicate changes to each other, however all directory writes are forced through one server at a time by the external frontend.

- Provides data consistency

- Does not support Delta Sync Repl (yet)

Unfortunately I do not have the capacity to test MirrorMode Replication, so I was hoping I could hear from someone who has practical experience with it to let me know if I'm off-base there.

Also, does N-Way Multi-Master Replication support Delta Sync Replication?  Unlike MirrorMode Replication which specifically denotes that it can't, the section on N-Way Multi-Master Replication doesn't implicitly say one way or another.  I guess I could assume then that it does, but I'd prefer not to - you know what they say about assumptions ;-)

Many thanks in advance,

Bob