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Re: Synchronous or asynchronous replication






From:	Quanah Gibson-Mount <quanah@zimbra.com>
To:	espeake@oreillyauto.com, openldap-technical@openldap.org
Date:	09/27/2013 03:49 PM
Subject:	Re: Synchronous or asynchronous replication
Sent by:	openldap-technical-bounces@OpenLDAP.org



--On Friday, September 27, 2013 2:46 PM -0500 espeake@oreillyauto.com
wrote:

>
> We have a 3 node N-Way Multi master set running 2.4.31.  I have been
> looking and trying to find a way to have asynchronous replication because
> synchronous replication is not required and we believe is actually
slowing
> us down.  I read in one article that by default n-way multi-master was
> doing asynchronous replication.  But then another article kind of mucked
> that up.  I ran through all of my db files with db_stat to get the
> internal pages and page size to be sure that my DB_Config was set with a
> large enough paging space and from my calculations it has more than
> enough.  Not enough to cache the entire db, but enough.
>
> So how can I be sure that we are using asynchronous replication with the
> n-way mulri master configuration.

What you should do is use delta-syncrepl based MMR with OpenLDAP 2.4.36.
Delta-syncrepl based MMR only replicates the exact changes that occurred,
rather than the entries, vastly reducing the amount of data being
transferred between nodes.  I would also recommend switching to back-mdb
with OpenLDAP 2.4.36, as it handles writes at *least* 50 times faster than
back-hdb/back-bdb.

I've already told you *multiple* times that there are known bugs with the
MMR code in 2.4.31, and you will end up having data issues, yet you
continue to ignore this.  Why, is beyond me.  Stop wasting your time and
everyone else's by insisting to run out of date code with known bugs.

--Quanah

--

Quanah Gibson-Mount
Lead Engineer
Zimbra Software, LLC
--------------------
Zimbra ::  the leader in open source messaging and collaboration

If I could get 2.4.35 or 2.4.36 to build a debian package as required by
our company I would use a newer version.  Every time I run the build it
errors out in the config.  So I have tried.  I can't do just a build I have
to be able to create the package for our puppet implementation.

Is there an update 2.4 admin doc out there that shows how to do this in a
dynamic setup instead of the slapd.conf.  Our MMR is working great with the
exception of one app that rebuilds groups and keeps them up to date.  this
application going against a single 2.4.21 version finished in an hour and
after 8 hours it is not completing.  Other than the replication, everything
is pretty much the same as far as cacheing and other DB tuning settings.

Sorry that I am wasting your time.
Eric
--
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