incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From aaron morton <aa...@thelastpickle.com>
Subject Re: hadoop/cassandra integration using CL_ONE...
Date Mon, 29 Jul 2013 08:08:06 GMT
> Is it possible to use CL_ONE with hadoop/cassandra when doing an M/R job?
That's the default. 
https://github.com/apache/cassandra/blob/cassandra-1.2/src/java/org/apache/cassandra/hadoop/ConfigHelper.java#L383

> And more importantly is there a way to configure that such that if my RF=3, that it only
reads from 1 of the nodes in that 3.
That's how it works AFAIK. 

> We have 12 nodes and ideally we would for example hope M/R runs on
> a2, a9, a5, a12 which happen to cover all token ranges.
> 
> This would leave a1, a3, a4, a6, a7, a8, a10, a11 to be free for the real-time work.
You could try only putting slots on those machines, not sure if that would work though.

The best way to isolate transactional and analytical load is to use multiple DC's. 

Cheers

-----------------
Aaron Morton
Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 27/07/2013, at 3:33 AM, "Hiller, Dean" <Dean.Hiller@nrel.gov> wrote:

> Is it possible to use CL_ONE with hadoop/cassandra when doing an M/R job? And more importantly
is there a way to configure that such that if my RF=3, that it only reads from 1 of the nodes
in that 3.
> 
> We have 12 nodes and ideally we would for example hope M/R runs on
> a2, a9, a5, a12 which happen to cover all token ranges.
> 
> This would leave a1, a3, a4, a6, a7, a8, a10, a11 to be free for the real-time work.
> 
> (That was just an example…obviously, I could pick another 4 nodes that cover all token
ranges).
> 
> Thanks,
> Dean


Mime
View raw message