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https://issues.apache.org/jira/browse/ZOOKEEPER-702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12900197#action_12900197
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Flavio Junqueira commented on ZOOKEEPER-702:
--------------------------------------------

Thanks for the comments, Ivan. I particularly agree with your point on building 
a list every time. I was actually wondering if there is any other important 
performance penalty we might be introducing. I can't think of any at the 
moment, but it be good to keep it in mind.  

The use of hbReceived and appMsgReceived does not bother me because they make 
more explicit what they do, but I agree it is more flexible the way you 
propose.  

Abmar, I went back to the papers and contrasted your implementation against the 
proposed algorithms. The only issue I could find is that the Bertier approach 
computes EA differently when j < n. I suggest we follow their description. The 
others seem fine to me.

> GSoC 2010: Failure Detector Model
> ---------------------------------
>
>                 Key: ZOOKEEPER-702
>                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-702
>             Project: Zookeeper
>          Issue Type: Wish
>            Reporter: Henry Robinson
>            Assignee: Abmar Barros
>         Attachments: bertier-pseudo.txt, bertier-pseudo.txt, chen-pseudo.txt, 
> chen-pseudo.txt, phiaccrual-pseudo.txt, phiaccrual-pseudo.txt, 
> ZOOKEEPER-702-code.patch, ZOOKEEPER-702-doc.patch, ZOOKEEPER-702.patch, 
> ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, 
> ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, 
> ZOOKEEPER-702.patch, ZOOKEEPER-702.patch, ZOOKEEPER-702.patch
>
>
> Failure Detector Module
> Possible Mentor
> Henry Robinson (henry at apache dot org)
> Requirements
> Java, some distributed systems knowledge, comfort implementing distributed 
> systems protocols
> Description
> ZooKeeper servers detects the failure of other servers and clients by 
> counting the number of 'ticks' for which it doesn't get a heartbeat from 
> other machines. This is the 'timeout' method of failure detection and works 
> very well; however it is possible that it is too aggressive and not easily 
> tuned for some more unusual ZooKeeper installations (such as in a wide-area 
> network, or even in a mobile ad-hoc network).
> This project would abstract the notion of failure detection to a dedicated 
> Java module, and implement several failure detectors to compare and contrast 
> their appropriateness for ZooKeeper. For example, Apache Cassandra uses a 
> phi-accrual failure detector (http://ddsg.jaist.ac.jp/pub/HDY+04.pdf) which 
> is much more tunable and has some very interesting properties. This is a 
> great project if you are interested in distributed algorithms, or want to 
> help re-factor some of ZooKeeper's internal code.

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