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From cass savy <>
Subject Re: Switching to Vnodes
Date Thu, 10 Dec 2015 00:02:27 GMT
We have 21 nodes in 3 DC, spark DC has 3 nodes. Primary datacenter nodes
has 300gb of data.

What the num_tokens you have in prod cluster? are u using default 256?

On Wed, Dec 9, 2015 at 2:19 PM, Victor Chen <> wrote:

> I have a 12 node cluster in prod using vnodes and C* version 2.18. I have
> never used rebuild, and instead prefer bootstrapping new nodes, even if it
> means there is additional shuffling of data and cleanup needed on the
> initial nodes in each DC, mostly b/c you can tell when bootstrapping is
> finished. w/ rebuild, like you have observed, there's really no way to be
> sure, apart from comparing load. I have no experience with vnodes and spark
> though, so I can't really comment on that. We are using secondary indexes
> though, and aren't seeing many issues. How much data do you have per node
> and in total and how many nodes?
> On Wed, Dec 9, 2015 at 4:26 PM, cass savy <> wrote:
>> We want to move our clusters to use Vnodes. I know the docs online say we
>> have to create new DC with vnodes and move to new dC and decommission old
>> one. We use DSE for our c* clusters.C* version is 2.0.14
>> 1. Is there any other way to migrate existing nodes to vnodes?
>> 2. What are the known issues with that approach?
>> 3. We have few secondary indexes in the keyspace, will that cause any
>> issues with moving to vnodes?
>> 4. What are the issues encountered after moving to vnodes in PROD
>> 5. anybody recommend Vnodes for Spark nodes.
>> *Approach : Moving to new DC with vnodes enabled*:
>> When I tested it for  a  keyspace which has secondary indexes, rebuilds
>> on Vnode enabled Datacenter takes days and don't know when it completes or
>> even if it will complete. I tried with 256,32,64 tokens per node but no
>> luck.
>> Please advise.

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