cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Clint Kelly <clint.ke...@gmail.com>
Subject Re: Why no virtual nodes for Cassandra on EC2?
Date Fri, 20 Feb 2015 16:29:59 GMT
Hi Mark,

Thanks for your reply.  That makes sense.  I recall looking at this
back when we were going to run Hadoop against data in Cassandra tables
at my previous company.

Disabling virtual nodes seems unfortunate as it would make (as I
understand it) scaling the cluster a lot trickier.  I assume there is
a tradeoff between the performance of analytics jobs and the ease with
which you can change cluster size.

-Clint



On Fri, Feb 20, 2015 at 1:01 AM, Mark Reddy <mark.l.reddy@gmail.com> wrote:
> Hey Clint,
>
> Someone for DataStax can correct me here, but I'm assuming that they have
> disabled vnodes because the AMI is built to make it easy to set up a
> pre-configured mixed workload cluster. A mixture of Real-Time/Transactional
> (Cassandra), Analytics (Hadoop), or Search (Solr). If you take a look at the
> getting started guide for both Hadoop and Solr you will see a paragraph
> instructing the user to disable vnodes for a mix workload cluster.
>
> http://www.datastax.com/documentation/datastax_enterprise/4.0/datastax_enterprise/srch/srchIntro.html
> http://www.datastax.com/documentation/datastax_enterprise/4.0/datastax_enterprise/ana/anaStrt.html
>
> This is specific to the example AMI and that type of workload. This is by no
> means a warning for users to disable vnodes on their Real-Time/Transactional
> Cassandra only clusters on EC2.
>
>
> I've used vnodes on EC2 without issue.
>
> Regards,
> Mark
>
> On 20 February 2015 at 05:08, Clint Kelly <clint.kelly@gmail.com> wrote:
>>
>> Hi all,
>>
>> The guide for installing Cassandra on EC2 says that
>>
>> "Note: The DataStax AMI does not install DataStax Enterprise nodes
>> with virtual nodes enabled."
>>
>>
>> http://www.datastax.com/documentation/datastax_enterprise/4.6/datastax_enterprise/install/installAMI.html
>>
>> Just curious why this is the case.  It was my understanding that
>> virtual nodes make taking Cassandra nodes on and offline an easier
>> process, and that seems like something that an EC2 user would want to
>> do quite frequently.
>>
>> -Clint
>
>

Mime
View raw message