RE: Applicability of LDAP Content Sync to loosely coupled replica sets

Kurt D. Zeilenga wrote:
> We did consider impacts of replication, mostly looking at
> single-master environments as this is what we are most familiar
> with and what LDAP models currently supports.

Maybe just a nit, but there do exist very widely deployed LDAP
directories that support loosely coupled DSAs tied together with
multi-master replication -- Active Directory and eDirectory, for two.  I
guess this issue has beaten into the ground on the list already, though.

> However, I
> believe that single-master environments have many of the same
> client update issues found in multi-master environments (when
> you consider issues between slaves which converge at different
> rates to their master).

Agreed -- I suppose I could have left the single- vs. multi-master part
out of my question, and simply stuck with "loosely coupled".

> >Is LDAP Content Sync intended to be applicable in this case?
> 
> Likely (but I'd have to think about it more).  I note that since
> LDAP Sync supports both updates+present and update+delete
> incremental synchronization mechanisms, if LCUP is applicable
> then likely so is LDAP Sync.

I'm not sure I agree there.  The key difference between LCUP and LDAP
Content Sync is the ability to assert the "member objects" without
forcing a reload.  The implication is that an incremental sync can force
the client to drop previous knowledge, which seems to be the heart of
the problematic example I illustrated.  LCUP doesn't have such a
mechanism; knowledge is lost only on a full reload.

If it were determined that dropping knowledge on incremental LDAP
Content Sync was too problematic (I don't know if this is true -- just
hypothetical) and dropped from the draft, then it seems to me that the
result would essentially be the same as LCUP.  Is that an overly
simplified viewpoint?

Thanks,
-J