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https://issues.apache.org/jira/browse/CASSANDRA-981?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12869181#action_12869181
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Jonathan Ellis commented on CASSANDRA-981:
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I think what we want to do is have the "dynamic" part just apply to 
endpoint-sorting, and leave replica determination up to the strategy in terms 
of DC + Rack.

A crappy alternative would be run-time loading of a new snitch (which could be 
hard-coded to sort whichever way).

> Dynamic endpoint snitch
> -----------------------
>
>                 Key: CASSANDRA-981
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-981
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>            Reporter: Jonathan Ellis
>             Fix For: 0.7
>
>
> An endpoint snitch that automatically and dynamically infers "distance" to 
> other machines without having to explicitly configure rack and datacenter 
> positions solves two problems:
> The killer feature here is adapting to things like compaction or a 
> failing-but-not-yet-dead disk.  This is important, since when we are doing 
> reads we pick the "closest" replica for actually reading data from (and only 
> read md5s from other replicas).  This means that if the closest replica by 
> network topology is temporarily slow due to compaction (for instance), we'll 
> have to block for its reply even if we get the other replies much much faster.
> Not having to manually re-sync your configuration with your network topology 
> when changes (adding machines) are made is a nice bonus.

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