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From AJ>
Subject Re: Docs: Token Selection
Date Fri, 17 Jun 2011 16:26:49 GMT
On 6/17/2011 7:26 AM, William Oberman wrote:
> I haven't done it yet, but when I researched how to make 
> geo-diverse/failover DCs, I figured I'd have to do something like 
> RF=6, strategy = {DC1=3, DC2=3}, and LOCAL_QUORUM for reads/writes. 
>  This gives you an "ack" after 2 local nodes do the read/write, but 
> the data eventually gets distributed to the other DC for a full 
> failover.  No "ying-yang", but I believe accomplishes the same goal?
> will

What I don't like about NTS is I would have to have more replicas than I 
need.  {DC1=2, DC2=2}, RF=4 would be the minimum.  If I felt that 2 
local replicas was insufficient, I'd have to move up to RF=6 which seems 
like a waste... I'm predicting data in the TB range so I'm trying to 
keep replicas to a minimum.

My goal is to have 2-3 replicas in a local data center and 1 replica in 
another dc.  I think that would be enough barring a major catastrophe.  
But, I'm not sure this is possible.  I define "local" as in the same 
data center as the client doing the insert/update.

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