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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "HedWig" by mahadevkonar
Date Tue, 11 Jan 2011 18:49:04 GMT
Dear Wiki user,

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The "HedWig" page has been changed by mahadevkonar.


  === Architecture ===
  At the highest level, Hedwig is a collection of *regions* spread across the internet. Any
region may publish on a topic, and those messages must be delivered to any subscriber in any
region that has subscribed to that topic.
- {{attachment:hedwig.png}}
+ {{attachment:hedwig_overview.png}}
  Now digging down into a region, it consists of a collection of '''hub servers'''. Hub servers
aggregate messages published in a region and persist them. They also subscribe to hubs in
other regions to listen for messages that their clients are subscribed to. Clients always
subscribe only to  local hub servers. Hedwig plans to use [[http://hadoop.apache.org/zookeeper/|Zookeeper]]
for persistence of metadata, and [[http://hadoop.apache.org/zookeeper/docs/r3.3.2/bookkeeperOverview.html|Bookkeeper]]
for persistence of actual messages.
- {{attachment:region_1.jpg}}
+ {{attachment:region_main1.jpg}}
  Topics are randomly split over hubs. When the hub responsible for a topic fails, another
hub should take over responsibility of the topic.

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