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From Jimmy Lin <y2klyf+w...@gmail.com>
Subject read consistency and clock drift and ntp
Date Wed, 11 Sep 2013 04:43:51 GMT
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

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