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Re: Slaving from Mirror Mode



Dear Quanah,

On 05/09/12 10:06 -0700, Quanah Gibson-Mount wrote:
--On Wednesday, September 05, 2012 7:00 PM +1000 Nick Urbanik <nick.urbanik@optusnet.com.au> wrote:

I am setting up mirror mode masters both in the same data centre,
with one slave offsite.  Should all the slaves slave from both
masters, or should they slave from a load balancer which decides
which master is getting the writes at present?

I'm never sure what you mean when you say the replica's should slave
from both masters.  A replica can only take updates from *one* master
for a given tree.  Your best option in your case is to set up MMR
where only one master is taking writes (mirror mode), and have the
replica use a load balanced name between the two masters as its
"master" for updates.  That should keep data consistent.

So you mean that all the slaves should slave through the load
balancer, as well as writes go through the load balancer?

I was going to set up the masters so that writes would go through the
load balancer, but slaves read from both masters like the multi-master
example shown at
http://www.openldap.org/doc/admin24/replication.html#N-Way%20Multi-Master
Thanks for that.

USE OF DELTA-SYNCREPL FROM MIRROR-MODE MASTER TO CONSUMERS
==========================================================

I have another question relating to section "18.3.4.1.2. Normal
Consumer Configuration" where there is this text:

  This is exactly the same as the Set up the consumer slapd
  section. It can either setup in normal syncrepl replication mode,
  or in delta-syncrepl replication mode.

So while I cannot use delta-syncrepl *between* the two mirror-mode
masters, I *can* use delta-syncrepl on our eight consumers slaving
*from* the current active master through the load balancer?  Is that
correct?

The eight consumers are what our clients read from.
--
Nick Urbanik             http://nicku.org           nicku@nicku.org
GPG: 7FFA CDC7 5A77 0558 DC7A 790A 16DF EC5B BB9D 2C24 ID: BB9D2C24