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From srmore <comom...@gmail.com>
Subject Re: Consistency level for multi-datacenter setup
Date Mon, 03 Jun 2013 20:37:56 GMT
Yup, RF is 2 for both the datacenters.


On Mon, Jun 3, 2013 at 3:36 PM, Sylvain Lebresne <sylvain@datastax.com>wrote:

> What's your replication factor? Do you have RF=2 on both datacenters?
>
>
> On Mon, Jun 3, 2013 at 10:09 PM, srmore <comomore@gmail.com> wrote:
>
>> I am a bit confused when using the consistency level for multi datacenter
>> setup. Following is my setup:
>>
>> I have 4 nodes the way these are set up are
>> Node 1 DC 1 - N1DC1
>> Node 2 DC 1 - N2DC1
>>
>> Node 1 DC 2 - N1DC2
>> Node 2 DC 2 - N2DC2
>>
>> I setup a delay in between two datacenters (DC1 and DC2 around 1 sec one
>> way)
>>
>> I am observing that when I use consistency level 2 for some reason the
>> coordinate node is picking up the nodes from other datacenter. My
>> understanding was that Cassandra picks up nodes which are close by (from
>> local datacenter), determined by Gossip but looks like that's not the case.
>>
>> I found the following comment on Datastax website :
>>
>> "If using a consistency level of ONE or LOCAL_QUORUM, only the nodes in
>> the same data center as the coordinator node must respond to the client
>> request in order for the request to succeed."
>>
>> Does this mean that for multi datacenter we can only use ONE or
>> LOCAL_QUORUM if we want to use the local datacenter to avoid cross
>> datacenter latency.
>>
>> I am using the GossipingPropertyFileSnitch.
>>
>> Thanks !
>>
>>
>

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