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Date: Sun, 22 Sep 2013 11:04:29 +0530
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Subject: Re: Questions About Master-Master Replication
From: Kiran Ayyagari <kayyagari@apache.org>
To: users@directory.apache.org
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On Sun, Sep 22, 2013 at 12:35 AM, Gareth Collins <gareth.o.collins@gmail.com
> wrote:

> Hello,
>
> I see that ApacheDS 2.0 supports Master-Master replication which is great
> (based on RFC 4533)! I understand that Master-Master replicas will have
> eventual consistency?
>
yes

>
> Are there any potential "gotchas" setting up Master-Master replication.
> e.g.:
>
> (1) Anything special you need to do in the case of a network partition?
>
> if a peer is unavailable then the server will keep checking for its
availability
in regular intervals and meanwhile stores all the modifications in a
log which will be sent when the peer come back online.

> (2) Are there any scenarios where Apache DS Master-Master instances
> can get into a state where they cannot synchronize (i.e. a conflict) which
> would require manual intervention? If yes, how would a user know that
> a conflict exists?
>
> not any that I have run into, but I will depend on the contextCSN value
stored in ou=system of each server to detect if they are in sync
i.e when two servers A and B are in M-M mode then they are in sync
if there is an entry Eb in B with the entryCSN attribute value matching with
the contextCSN value of A and vice versa.

Any info here, would be a bug help!
>
> thanks in advance,
> Gareth
>


-- 
Kiran Ayyagari
http://keydap.com

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