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Re: understanding replication
Aaron Richton wrote:
On Mon, 1 Mar 2010, Alan Batie wrote:
I'm a little puzzled by the openldap replication docs; in particular
rid, entryuuid, entrycsn, contextcsn fields that I see referenced a lot.
Basically, I'd like to understand the replication process at a slightly
higher level than http://www.openldap.org/doc/admin24/syncrepl.html
describes not quite completely enough...
In addition to the Admin Guide, I suggest reading RFC4533 and the other
material in the doc/ directory of the distribution. Also, even if you're
not particularly adept at C, you may wish to read the comments in
syncprov.c source file. The terms you're asking about are the names that
OpenLDAP uses in its implementation; hopefully with the RFC in hand it
will become clear how the concepts map to the names, and you can always
ask if anything is still unclear.
I'm guessing the rid is a random chosen id number for the secondary
server (consumer?) that is used to compare the master db (entryuuid?)
for context? information that indicates sync state?
rid is chosen by administrator (i.e. manually configured). I honestly
forget what it's used for nowadays...I vaguely remember "nothing" and/or
"it's only important for multimaster." I'm certain this is in the archives
of openldap-software and/or openldap-devel, but I'll leave the search to
Like the manpage says:
rid identifies the current syncrepl directive within the replication consumer
It's only use is to give the slapd -c option something to reference. Nothing else.
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/