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Date: Thu, 2 Dec 2010 11:11:02 -0600
Message-ID: <AANLkTinqkNx7eKB9J+6=BFEyoMmk7tC7-FXgVz-YsxW=@mail.gmail.com>
Subject: Re: Best Practice for Data Center Migration
From: Jonathan Ellis <jbellis@gmail.com>
To: user <user@cassandra.apache.org>
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On Thu, Dec 2, 2010 at 4:08 AM, Jake Maizel <jake@soundcloud.com> wrote:
> Hello,
>
> We have a ring of 12 nodes with 6 in one data center and 6 in another.
> =A0We want to shutdown all 6 nodes in data center 1 in order to close
> it down. =A0We are using a replication factor of 3 and are using
> RackAwareStrategy with version 0.6.6.
>
> We have been thinking that using decomission on each of the nodes in
> the old data center one at a time would do the trick. =A0Does this sound
> reasonable?

That is the simplest approach.  The major downside is that
RackAwareStrategy guarantees you will have at least one copy of _each_
row in both DCs, so when you are down to 1 node in dc1 it will have a
copy of all the data.  If you have a small enough data volume to make
this feasible then that is the option I would go with.

> We have also been considering increasing the replication factor to 4
> and then just shutting down all the old nodes. =A0Would that work as far
> as data availability would go?

Not sure what you are thinking of there, but probably not. :)

--=20
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com