Shrinking cluster with counters ...

[Ian Danforth <id...@numenta.com>]

All,

 If I have a 3 node cluster storing counters and RF3, is it possible to
shrink back down to a single node cluster? If so should I change replication
factor, disable a node, wait for streaming to complete, and repeat for the
other node? Should I assume that the cluster will be unavailable during this
process?

Thanks in advance!

Ian

Re: Shrinking cluster with counters ...

[aaron morton <aa...@thelastpickle.com>]

Is the cluster still in use ? 

The safe way would be to reduce the RF to 1, and then nodetool decomission the nodes one at a time. This will cause them to stream data to the remaining node(s), and at the same time the node that takes ownership will be receiving writes for the new token range. It does mean you have some data transfers which are wasted. 

If the cluster is not in use a faster way would be to ensure repair completes on node and then use nodetool removetoken (from a node other than the one you want to remove) to remove it from the ring without streaming data. 

I would go with the first option. 

Cheers


-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 5/10/2011, at 11:56 AM, Ian Danforth wrote:

> All,
> 
>  If I have a 3 node cluster storing counters and RF3, is it possible to shrink back down to a single node cluster? If so should I change replication factor, disable a node, wait for streaming to complete, and repeat for the other node? Should I assume that the cluster will be unavailable during this process?
> 
> Thanks in advance!
> 
> Ian
>