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 <CAPwwW9GWXEJo+cXWzWs3=UoS-MO9vAVdndg4esZCRCRAg2A-Ng@mail.gmail.com>
Subject: Journal Nodes in a multi-site environment
To: user@ambari.apache.org
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--001a1134a45c57ae5504ed424ebe
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Hi all,

I have an Ambari 1.4/HDP 2.0.6 environment that is split between two data
centers -- a main site and a recovery site.  We have NameNode HA enabled
with automatic failover and the problem we are facing is how to divide the
journal nodes across both sites so that failover happens appropriately.

It seems that only one site will always have a majority of journal nodes
and if that site NN were to go down, the other site NN would no longer be
able to start as it couldn't reach a majority of the journal nodes.

Is there any way around this?  I know an odd number of journal nodes is
recommended but what would happen if we were to place an even number of
journal nodes at each site?

Thanks for any input!

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<div dir=3D"ltr">Hi all,<div><br></div><div>I have an Ambari 1.4/HDP 2.0.6 =
environment that is split between two data centers -- a main site and a rec=
overy site. =A0We have NameNode HA enabled with automatic failover and the =
problem we are facing is how to divide the journal nodes across both sites =
so that failover happens appropriately.</div>

<div><br></div><div>It seems that only one site will always have a majority=
 of journal nodes and if that site NN were to go down, the other site NN wo=
uld no longer be able to start as it couldn&#39;t reach a majority of the j=
ournal nodes.</div>

<div><br></div><div>Is there any way around this? =A0I know an odd number o=
f journal nodes is recommended but what would happen if we were to place an=
 even number of journal nodes at each site?</div><div><br></div><div>Thanks=
 for any input!</div>

</div>

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