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From aaron morton <aa...@thelastpickle.com>
Subject Re: Help on how to configure an off-site DR node.
Date Tue, 29 Mar 2011 10:56:32 GMT
Be aware that at RF 2 the Quorum is 2, so you cannot afford to lose a replica when working
at Quorum. 3 is really the starting point if you want some redundancy. 

If you want to get your data offsite how about doing snapshots and moving them off site http://wiki.apache.org/cassandra/Operations#Consistent_backups

The guide from Data Stax will give you a warm failover site, which sounds a bit more than
what you need.  

Hope that helps. 
Aaron

On 28 Mar 2011, at 22:47, Brian Lycett wrote:

> Hello.
> 
> I'm setting up a cluster that has three nodes in our production rack.
> My intention is to have a replication factor of two for this.
> For disaster recovery purposes, I need to have another node (or two?)
> off-site.
> 
> The off-site node is entirely for the purpose of having an offsite
> backup of the data - no clients will connect to it.
> 
> My question is, is it possible to configure Cassandra so that the
> offsite node will have a full copy of the data set?
> That is, somehow guarantee that a replica of all data will be written to
> it, but without having to resort to an ALL consistency level for writes?
> Although the offsite node will on a 20Mbit leased line, I'd rather not
> have the risk that the link goes down and breaks the cluster.
> 
> I've seen this suggestion here:
> http://www.datastax.com/docs/0.7/operations/datacenter#disaster
> but that configuration is vulnerable to the link breaking, and uses four
> nodes in the offsite location.
> 
> 
> Regards,
> 
> Brian
> 
> 


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