MirrorMode vs MultiMaster Questions

[Ben Rockwood <benr@cuddletech.com>]

I'm having some problems understanding the subtleties of MirrorMode vs
MultiMaster configurations.  Any help with the following questions would
be helpful:

1) It looks like the only real difference between a MirrorMode and
Multimaster configuration is whether or not the RIDs are different.  In
MirrorMode both sides have the same rid, in Multimaster they are
different.  Is that so?

2) Passing through the code, "MirrorMode" is really "Single Master" and
MultiMaster is just "not Single Master".  But the code path to determine
whether it is single master or not confuses me.  How does slapd actually
determine this? 

3) For MultiMaster, the docs show using syncrepl to replicate cn=config
and the directory (or directories if you have more than one)
independently.  Is it really necessary to replicate cn=config if the
configuration isn't changing?  (What I'm really looking for here is to
find out if there is state information in cn=config thats being used or
if its simply a good idea to ensure the configs are the same by using
syncrepl.)


Thanks,

benr.