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From rash aroskar <rashmi.aros...@gmail.com>
Subject Re: cassandra 1.2.5- virtual nodes (num_token) pros/cons?
Date Fri, 09 Aug 2013 23:39:51 GMT
Aaron - I read about the virtual nodes at
http://www.datastax.com/dev/blog/virtual-nodes-in-cassandra-1-2








On Tue, Aug 6, 2013 at 4:49 AM, Richard Low <richard@wentnet.com> wrote:

> On 6 August 2013 08:40, Aaron Morton <aaron@thelastpickle.com> wrote:
>
>> The reason for me looking at virtual nodes is because of terrible
>> experiences we had with 0.8 repairs and as per documentation (an logically)
>> the virtual nodes seems like it will help repairs being smoother. Is this
>> true?
>>
>> I've not thought too much about how they help repair run smoother, what
>> was the documentation you read ?
>>
>
> There might be a slight improvement but I haven't observed any.  The
> difference might be that, because every node shares replicas with every
> other (with high probability), a single repair operation does the same work
> on the node it was called on, but the rest is spread out over the cluster,
> rather than just the RF nodes either side of the repairing node.  This
> means the post-repair compaction work will take less time and the length of
> time a node is loaded for during repair is less.
>
> However, the other benefits of vnodes are likely to be much more useful.
>
> Richard.
>

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