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From Robert Jackson <robe...@promedicalinc.com>
Subject Re: Continuous export of data out of database
Date Tue, 15 Nov 2011 19:04:01 GMT
It would work if you could use LOCAL_QUORUM in each independent data center, but with EACH_QUORUM
the whole read/write operation would block until a quorum was reached in each data center.
This would be particularly bad if using a single replica in the "backup" data center and it
was unavailable (the read/write would fail). 

Unfortunately , I can't think of another solution with Cassandra itself. You could use some
sort of client side queueing and keep the two clusters separated completely. This would probably
add quite a bit of complexity to your app... 

Robert Jackson 
----- Original Message -----

| From: "A J" <s5alye@gmail.com>
| To: user@cassandra.apache.org
| Sent: Tuesday, November 15, 2011 12:20:52 PM
| Subject: Re: Continuous export of data out of database

| The issue with that is that I wish to have EACH_QUORUM in our other 2
| datacenters but not in the third DC.
| Could not figure a way to accomplish that so exploring have a
| near-realtime backup copy in the third DC via some streaming process.

| On Tue, Nov 15, 2011 at 12:12 PM, Robert Jackson
| <robertj@promedicalinc.com> wrote:
| > The thing that I thought if initially would be setting up your
| > cluster in a
| > multi-datacenter config[1]. In that scenario you could add an
| > additional
| > machine in a second datacenter with RF=1. We are using a variant of
| > this
| > setup to separate long running calculations from our interactive
| > systems.
| > [1] -
| > http://www.datastax.com/dev/blog/deploying-cassandra-across-multiple-data-centers
| >
| > Robert Jackson
| > ________________________________

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