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From "B. Todd Burruss" <bto...@gmail.com>
Subject Re: High bandwidth usage between datacenters for cluster
Date Thu, 01 Nov 2012 15:17:04 GMT
bryce, did you resolve this?  i'm interested in the outcome.

when you write does it help to use CL = LOCAL_QUORUM?

On Mon, Oct 29, 2012 at 12:52 AM, aaron morton <aaron@thelastpickle.com> wrote:
> Outbound messages for other DC's are grouped and a single instance is sent
> to a single node in the remote DC. The remote node then forwards the message
> on to the other recipients in it's DC. All remote DC nodes will however
> reply directly to the coordinator.
>
> Normally this isn’t an issue for us, but at times we are writing
> approximately 1MB a sec of data, and seeing a corresponding 3MB of traffic
> across the WAN to all the Cassandra DR servers.
>
> Can you break the traffic down by port and direction ?
>
> Cheers
>
>
>
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 28/10/2012, at 12:18 PM, Bryce Godfrey <Bryce.Godfrey@azaleos.com> wrote:
>
> Network topology with the topology file filled out is already the
> configuration we are using.
>
> From: sankalp kohli [mailto:kohlisankalp@gmail.com]
> Sent: Thursday, October 25, 2012 11:55 AM
> To: user@cassandra.apache.org
> Subject: Re: High bandwidth usage between datacenters for cluster
>
> Use placement_strategy =
> 'org.apache.cassandra.locator.NetworkTopologyStrategy' and also fill the
> topology.properties file. This will tell cassandra that you have two DCs.
> You can verify that by looking at output of the ring command.
>
> If you DCs are setup properly, only one request will go over WAN. Though the
> responses from all nodes in other DC will go over WAN.
>
> On Thu, Oct 25, 2012 at 10:44 AM, Bryce Godfrey <Bryce.Godfrey@azaleos.com>
> wrote:
>
> We have a 5 node cluster, with a matching 5 nodes for DR in another data
> center.   With a replication factor of 3, does the node I send a write too
> attempt to send it to the 3 servers in the DR also?  Or does it send it to 1
> and let it replicate locally in the DR environment to save bandwidth across
> the WAN?
> Normally this isn’t an issue for us, but at times we are writing
> approximately 1MB a sec of data, and seeing a corresponding 3MB of traffic
> across the WAN to all the Cassandra DR servers.
>
> If my assumptions are right, is this configurable somehow for writing to one
> node and letting it do local replication?  We are on 1.1.5
>
> Thanks
>
>

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