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From AJ>
Subject Re: Propose new ConsistencyLevel.ALL_AVAIL for reads
Date Fri, 17 Jun 2011 05:01:29 GMT
On 6/16/2011 9:36 PM, Dan Hendry wrote:
> "Help me out here.  I'm trying to visualize a situation where the 
> clients can access all the C* nodes but the nodes can't access each 
> other.  I don't see how that can happen on a regular ethernet subnet 
> in one data center.  Well, I"m sure there is a case that you can point 
> out.  Ok, I will concede that this is an issue for some network 
> configurations."
> First rule of designing/developing/operating distributed systems: 
> assume anything and everything can and will happen, regardless of 
> network configuration or hardware.
> This specific situation actually HAS happened to me. Our Cassandra 
> nodes accept client connections on one ethernet interface on one 
> network (the production network) yet communicate with each other on a 
> separate ethernet interface on a separate network which is Cassandra 
> specific. This was done mainly due to the relatively large inter-node 
> Cassandra bandwidth requirements in comparison to client bandwidth 
> requirements. At one point, the switch for the cassandra network went 
> down so clients could connect yet the cassandra nodes could not talk 
> to eachother. (We write at ONE and read at ALL so everything behaved 
> as expected).

Funny, but that's the exact same setup I'm running.  But, I'm not a 
network guy and kind of assumed it wasn't so typical.  Plus, lately I've 
had my mind on a cloud setup.

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