[Hadoop Wiki] Update of "ZooKeeper/SoC2010Ideas" by HenryRobinson

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The "ZooKeeper/SoC2010Ideas" page has been changed by HenryRobinson.
http://wiki.apache.org/hadoop/ZooKeeper/SoC2010Ideas

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New page:
= ZooKeeper Google Summer of Code 2010 Ideas Page =

<<TableOfContents(3)>>

Please update this page with ideas you'd like to see a SoC student implement in ZooKeeper over the summer. A good project is about 3 months long and has well defined success criteria. 

If you are willing and able to mentor a student in any project you see below that doesn't currently have a mentor, please update the idea with your name. 

More details about Google's Summer of Code can be found here: http://socghop.appspot.com/document/show/gsoc_program/google/gsoc2010/faqs - the deadline for our applications is Friday, so get those ideas coming in!

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=== Optimizations for WAN Deployments ===
==== Possible Mentor ====
Henry Robinson (henry at apache dot org)
==== Requirements ====
Java, some networking familiarity
==== Description ====
ZK 3.3.0 added ''observers'' which are non-voting members of a ZK ensemble. One use case for observers is as a proxy to a remote voting ensemble, say in a different data center. Since observers do not need to vote, there are less strict latency requirements on the delivery of messages to them. WAN traffic is also expensive. This project would investigate and implement batching of messages to observers, and potential mechanisms for decreasing the number of messages that need to be sent. For example, a destructive update to a znode twice in a row does not theoretically need to be sent twice - although making this work correctly with ZAB will be a challenge.