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From James Golick <jamesgol...@gmail.com>
Subject Re: Uneven distribution using RP
Date Tue, 22 Jun 2010 17:31:47 GMT
RackUnaware, currently

On Tue, Jun 22, 2010 at 1:26 PM, Robert Coli <rcoli@digg.com> wrote:

> On 6/22/10 10:07 AM, James Golick wrote:
>
>> This node's load is now growing at a ridiculous rate. It is at 105GB, with
>> the next most loaded node at 70.63GB.
>>
>> Given that RF=3, I would assume that the replicas' nodes would grow
>> relatively quickly too?
>>
> What Replica Placement Strategy are you using (Rackunaware, Rackaware,
> etc?)? The current implementation of Rackaware is pretty simple and relies
> on careful placement of nodes in multiple DCs along the ring to avoid
> hotspots.
>
> http://wiki.apache.org/cassandra/Operations#Replication
> "
> RackAwareStrategy: replica 2 is placed in the first node along the ring the
> belongs in another data center than the first; the remaining N-2 replicas,
> if any, are placed on the first nodes along the ring in the same rack as the
> first
>
> Note that with RackAwareStrategy, succeeding nodes along the ring should
> alternate data centers to avoid hot spots. For instance, if you have nodes
> A, B, C, and D in increasing Token order, and instead of alternating you
> place A and B in DC1, and C and D in DC2, then nodes C and A will have
> disproportionately more data on them because they will be the replica
> destination for every Token range in the other data center.
> "
>
> https://issues.apache.org/jira/browse/CASSANDRA-785
>
> Is also related, and marked Fix Version 0.8.
>
> =Rob
>
>

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