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Posted to user@cassandra.apache.org by zhiming shen <zh...@gmail.com> on 2012/04/05 05:31:41 UTC
Will Cassandra balance load across replicas?
Hi,
Can any one tell me whether Cassandra can do load balancing across
replicas? How to configure it for this purpose? Thanks very much.
Best Regards,
Zhiming
Re: Will Cassandra balance load across replicas?
Posted by Rob Coli <rc...@palominodb.com>.
On Thu, Apr 5, 2012 at 9:22 AM, zhiming shen <zh...@gmail.com> wrote:
> Thanks for your reply. My question is about the impact of replication on
> load balancing. Say we have nodes ABCD... in the ring. ReplicationFactor is
> 3 so the data on A will also have replicas on B and C. If we are reading
> data own by A, and A is already very busy, will the requests be forwarded to
> B and C? How about update requests?
Google "cassandra dynamic snitch".
--
=Robert Coli
AIM>ALK - rcoli@palominodb.com
YAHOO - rcoli.palominob
SKYPE - rcoli_palominodb
Re: Will Cassandra balance load across replicas?
Posted by Watanabe Maki <wa...@gmail.com>.
In your case, cassandra will read the data from the nearest node, and read digest from other two nodes.
When those read meet requested consistency level, cassandra will return the result.
maki
From iPhone
On 2012/04/06, at 1:22, zhiming shen <zh...@gmail.com> wrote:
> Thanks for your reply. My question is about the impact of replication on load balancing. Say we have nodes ABCD... in the ring. ReplicationFactor is 3 so the data on A will also have replicas on B and C. If we are reading data own by A, and A is already very busy, will the requests be forwarded to B and C? How about update requests?
>
>
> Thanks,
>
>
> Zhiming
>
> On Thu, Apr 5, 2012 at 12:33 AM, Watanabe Maki <wa...@gmail.com> wrote:
> I assume you are talking about nodes, rather than replicas.
> The data distribution over ring depends on Partitioner and Replica placement strategy you use.
> If you are using Random Partitioner and Simple Strategy, your data will be automatically distributed over the nodes in the ring.
>
> maki
>
>
> On 2012/04/05, at 12:31, zhiming shen <zh...@gmail.com> wrote:
>
> > Hi,
> >
> > Can any one tell me whether Cassandra can do load balancing across replicas? How to configure it for this purpose? Thanks very much.
> >
> >
> > Best Regards,
> >
> > Zhiming
>
Re: Will Cassandra balance load across replicas?
Posted by zhiming shen <zh...@gmail.com>.
Thanks for your reply. My question is about the impact of replication on
load balancing. Say we have nodes ABCD... in the ring. ReplicationFactor is
3 so the data on A will also have replicas on B and C. If we are reading
data own by A, and A is already very busy, will the requests be forwarded
to B and C? How about update requests?
Thanks,
Zhiming
On Thu, Apr 5, 2012 at 12:33 AM, Watanabe Maki <wa...@gmail.com>wrote:
> I assume you are talking about nodes, rather than replicas.
> The data distribution over ring depends on Partitioner and Replica
> placement strategy you use.
> If you are using Random Partitioner and Simple Strategy, your data will be
> automatically distributed over the nodes in the ring.
>
> maki
>
>
> On 2012/04/05, at 12:31, zhiming shen <zh...@gmail.com> wrote:
>
> > Hi,
> >
> > Can any one tell me whether Cassandra can do load balancing across
> replicas? How to configure it for this purpose? Thanks very much.
> >
> >
> > Best Regards,
> >
> > Zhiming
>
Re: Will Cassandra balance load across replicas?
Posted by Watanabe Maki <wa...@gmail.com>.
I assume you are talking about nodes, rather than replicas.
The data distribution over ring depends on Partitioner and Replica placement strategy you use.
If you are using Random Partitioner and Simple Strategy, your data will be automatically distributed over the nodes in the ring.
maki
On 2012/04/05, at 12:31, zhiming shen <zh...@gmail.com> wrote:
> Hi,
>
> Can any one tell me whether Cassandra can do load balancing across replicas? How to configure it for this purpose? Thanks very much.
>
>
> Best Regards,
>
> Zhiming