Date: Tue, 21 Aug 2012 07:56:20 -0700
To: ctcard(a)hotmail.com; openldap-technical(a)openldap.org
Subject: RE: multi-master syncrepl issue
--On Tuesday, August 21, 2012 2:50 PM +0000 Chris Card <ctcard(a)hotmail.com>
>> Do you have sync logging enabled?
> Log level is set to none, so the slapd log doesn't give much help.
Fix your log level.
olcLogLevel: sync ?
>> In any case, with a server that large (3.5 million entries), I expect it
>> will generally take a few months for it to catch up, since with standard
>> syncrepl, it is going to try and refresh the entire database if it passed
>> your sync ops log. I would strongly advise delta-syncrepl MMR instead,
>> although that may take a significant amount of disk space for such a
>> large DB if it is heavily active.
> The initial load of the directory via replication took < 2 days, so why
> would it take months to catch up? I tried restarting slapd with the -c
> flag specifying the current csn of the database, but it didn't seem to
> make any difference - is that expected?
> I'll take a look at using delta-syncrepl, since disk space isn't an issue.
Syncrepl is slow, and your database will have constant changes even while
replication is ongoing -- So if in 2 days it is caught up to where the
other servers were two days ago, it will have to go back through and
restart comparisons. So it may take well under a month, the point is, it
will take a significant amount of time.
Would you expect catch-up with
delta-syncrepl to much faster?
In addition, it is going to have
to take changes from 4 servers, which may cause deadlocks and other issues
in the DB, assuming you're using BDB as the backend.
There are 4 servers, but all the changes go to one of them, the others are there as
read-only servers, so
I don't expect problems with deadlocking. I am also looking into mdb, but that's
for another thread.