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