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From Jimmy Lin <>
Subject read consistency and clock drift and ntp
Date Wed, 11 Sep 2013 04:43:51 GMT
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)


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