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From Jonathan Ellis <>
Subject Re: Best Practice for Data Center Migration
Date Thu, 02 Dec 2010 17:11:02 GMT
On Thu, Dec 2, 2010 at 4:08 AM, Jake Maizel <> wrote:
> Hello,
> We have a ring of 12 nodes with 6 in one data center and 6 in another.
>  We want to shutdown all 6 nodes in data center 1 in order to close
> it down.  We 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.  Does 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.  Would that work as far
> as data availability would go?

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

Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support

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