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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "ZooKeeper/ServiceLatencyOverview" by PatrickHunt
Date Wed, 28 Oct 2009 05:33:27 GMT
Dear Wiki user,

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The "ZooKeeper/ServiceLatencyOverview" page has been changed by PatrickHunt.


  All systems had 7200RPM SATA drives. hdparm reported:
   * Timing cached reads:   22980 MB in  1.99 seconds = 11532.40 MB/sec
   * Timing buffered disk reads:  266 MB in  3.01 seconds =  88.29 MB/sec
- During the tests the snapshot (on disk copy of the znode data) reached approximately 100meg
in size (as mentioned previously the JVM heap is limited to 512 meg), by default transactional
log files are pre-allocated to ~60meg. Additional snapshots and logs are written as needed.
Depending on your workload, the frequency of your snap/log cleanup, and your cluster configuration
you should allow sufficient storage space. For example running a 20 client test required approximately
5 gig of disk storage. (the tests were not cleaning up old snaps/logs, so this was accumulated
over the test lifetime).
  All systems are interconnected with 1gig ethernet, approximate ping time is steady at 0.09ms

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