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From Sasha Dolgy <sdo...@gmail.com>
Subject Re: EC2 node adding trouble
Date Thu, 26 May 2011 13:21:32 GMT
On Thu, May 26, 2011 at 3:12 PM, Marcus Bointon
<marcus@synchromedia.co.uk> wrote:
> I'd like to make sure I've got the right sequence of operations for adding a node without
downtime. If I'm going from 2 to 3 nodes:
>
> 1 Calculate new initial_token values using the python script
> 2 Change token values in existing nodes and restart them
> 3 Install/configure new node
> 4 Insert new node's token value
> 5 Set new node to auto-bootstrap
> 6 Start cassandra on new node
> 7 Wait for the ring to rebalance
>
> With token changes (using values from the python script), it's clear that all nodes will
have some data moved. Does this mean that there's a possibility of overlap between regions
if token changes are not absolutely simultaneous on all nodes? That sounds dangerous to me...
Or shouldn't token values be changed on nodes containing data?
>

nodetool repair is good.  when we add new nodes, we add a new one
without specifying the new token.  after everything is up and healthy,
we determine new tokens and see if there is a need to renumber nodes.
if we do, we do one at a time and wait until the nodetool repair is
finished on one node before moving to another....

> Is there a corresponding sequence for removing nodes? I'm guessing draining is involved.

Turn the node off, remove the node from the ring using nodetool and
removetoken .... i've found this to be the best problem-free way.
Maybe it's better now ...
http://blog.sasha.dolgy.com/2011/03/apache-cassandra-nodetool.html

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