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From Paulo Motta <pauloricard...@gmail.com>
Subject Re: read consistency and clock drift and ntp
Date Wed, 11 Sep 2013 12:28:25 GMT
Here some links related do C* and clock synchronization:

http://www.datastax.com/dev/blog/why-cassandra-doesnt-need-vector-clocks

http://ria101.wordpress.com/2011/02/08/cassandra-the-importance-of-system-clocks-avoiding-oom-and-how-to-escape-oom-meltdown/




2013/9/11 Jimmy Lin <y2klyf+work@gmail.com>

> hi,
> I have few question around the area how Cassandra use record's timestamp
> to determine which one to return from its replicated nodes ...
>
> -
> A record's timestamp is determined by the Cassandra server node's system
> timestamp when the request arrive the server and NOT by the client
> timestamp who make the request(unlike timeuuid)??
>
> -
> so clock synchronization between nodes is very important , clock drifting
> however is still possible even if one use NTP? I wonder what are the common
> practices in Cassandra community do to minimize clock drifting?
>
> -
> is there a recommend maximum drifting allowed in a cluster before things
> can get very ugly?
>
> -
> how to determine if two nodes in a cluster have out of sync clock?
> (as monitor or alert so appropriate action can be taken)
>
> Thanks
>
>
>
>
>
>



-- 
Paulo Ricardo

-- 
European Master in Distributed Computing***
Royal Institute of Technology - KTH
*
*Instituto Superior T├ęcnico - IST*
*http://paulormg.com*

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