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From Michael Shuler <mich...@pbandjelly.org>
Subject Re: Multi datacenter node loss
Date Thu, 20 Jul 2017 20:56:25 GMT
Datacenter replication is defined in the keyspace schema, so I believe that
  ...
  WITH replication = {'class': 'NetworkTopologyStrategy', 'DC1': 1,
'DC2': 1}
  ...
you ought to be able to repair DC1 from DC2, once you have the DC1 node
healthy again.

If using the SimpleStrategy replication class, it appears that
replication_factor is the only option, which applies to the entire
cluster, so only one node in both datacenters would have the data.

https://cassandra.apache.org/doc/latest/cql/ddl.html#create-keyspace

-- 
Kind regards,
Michael

On 07/20/2017 03:23 PM, Roger Warner wrote:
> Hi
> 
>  
> 
> I’m a little dim on what multi datacenter implies in the 1 replica
> case.     I know about replica recovery, how about “node recovery”
> 
>  
> 
> As I understand if there a node failure or disk crash with a single node
> cluster with replication factor 1 I lose data.    Easy.
> 
>  
> 
> nodetool tells me each node in my 3 node X 2 datacenters is responsible
> for ~1/3 of the data.    If in this cluster with RF=1 a node fails in
> dc1 what happens ? in 1 dc with data loss can the node be “restored”
> from a node in dc2?.  Automatically?
> 
>  
> 
> I’m also asking tangentially how does the data map from nodes in dc1 to
> dc2.
> 
>  
> 
> I hope I made that coherent.
> 
>  
> 
> Roger
> 


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