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Re: Feature request: multimaster

Greetings LDAP Developers. I have been lurking on the list waiting to see if
the topic of multimaster would come up as there is no mention of it on the web
site. I was unclear if such a topic would be considered on this list, from
watching the thread obviously it is! ;-)

On Tue, 08 Feb 2005 00:02:09 -0800, Morteza Ansari wrote:

>Wouldn't conflict resolution be a must for this?

Wouldn't it depend on what kind of data is in the DSA? One place I see the need
for multimaster is in a WAN environment where each site would get a LDAP
server, Samba would utilize the DSA for user objects. An LDAP server at each
site allows users to log in to the Samba PDC while the WAN link is down. Users
can also change passwords. So, when the WAN link comes back up and LDAP
replication returns, some user objects in the remote site DSA would be newer
than the rest of the LDAP servers, thus replicate out. At other sites user
objects would have been updated, thus they would replicate down.

I developed this sort of a system one in RDBMS where two date fields were added
to each row. A replicate job would utilize those dates to decide which records
need to replicate, and if both sides had changed that record since the last

I believe Lotus Notes uses much the same design. Everything is fine until two
"remotes" update the same object without knowing the other updated. Notes shows
that as a replication conflict.

Again, based on what kind of data is in the DSA the response to a replication
conflict would indeed be different.

Back to Samba, "what if" user A at remote site with the WAN down changes their
password, plus some admin makes some change to the same user objects back at
the home site. Up comes the WAN, both sides updated, hhhhmmmm....

So, one vote for implementation specific replication conflict resolution

Michael Lueck
Lueck Data Systems