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Date: Thu, 01 Nov 2012 17:00:44 +0900
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To: user@cassandra.apache.org
Subject: Re: Data migration between clusters
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Hi Rob,

Thank you for your reply.
Our scenario is like this, we have 3 clusters, each has 1 or 2 keyspaces 
in it,
and each cluster has 3 nodes.
Now we're considering integrating these 3 clusters of 9 nodes to a 
single cluster of 9 nodes.
This new cluster will contain all keyspaces and their data the former 3 
clusters have.
The replication factor, which is 3 now, will not be changed during this 
migration.
We tried using sstableloader which didn't work well. Maybe we did it in 
a wrong way.
It looks like the way of migrating data you suggested would solve our 
problem,
we'll try it out by refering the link you gave in your mail.

Thanks a lot again for your precious information,
Ray

(12/11/01 2:43), Rob Coli wrote:
> On Tue, Oct 30, 2012 at 4:18 AM, 張　睿 <chou_ei@cyberagent.co.jp> wrote:
>> Does anyone here know if there is an efficient way to migrate multiple
>> cassandra clusters' data
>> to a single cassandra cluster without any dataloss.
> Yes.
>
> 1) create schema which is superset of all columnfamilies and all keyspaces
> 2) if all source clusters were the same fixed number of nodes, create
> a new cluster with the same fixed number of nodes
> 3) nodetool drain and shut down all nodes on all participating clusters
> 4) copy sstables from old clusters, maintaining that data from source
> node [x] ends up on target node [x]
> 5) start cassandra
>
> However without more details as to your old clusters, new clusters,
> and availability requirements, I can't give you a more useful answer.
>
> Here's some background on bulk loading, including "copy-the-sstables."
>
> http://palominodb.com/blog/2012/09/25/bulk-loading-options-cassandra
>
> =Rob
>

-- Ray Zhang Cyberagent.co