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https://issues.apache.org/jira/browse/SOLR-5476?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13896024#comment-13896024
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Mark Miller commented on SOLR-5476:
-----------------------------------

To sum up an offline conversation Noble and I had about this:

I'm not happy with the approach, I think it's dangerous, and I'm worried about 
making more and more of these types of exceptions.

However, I will withdraw my -1 on it if the testing is significantly beefed up 
and it can be proved the current approach is usually not going to screw you. I 
think the current test is an absolute minimum test and it has regularly failed 
on jenkins (and for me locally even more fequently) since it was committed.

We also agreed on a JIRA issue to come up with a better approach at some point.

I also think we need to add some defensive programming. If we try and remove a 
queue item that is not there, we should assume another overseer already ate it 
rather than letting the Overseer thread die.

> Overseer Role for nodes
> -----------------------
>
>                 Key: SOLR-5476
>                 URL: https://issues.apache.org/jira/browse/SOLR-5476
>             Project: Solr
>          Issue Type: Sub-task
>          Components: SolrCloud
>            Reporter: Noble Paul
>            Assignee: Noble Paul
>             Fix For: 5.0, 4.7
>
>         Attachments: SOLR-5476.patch, SOLR-5476.patch, SOLR-5476.patch, 
> SOLR-5476.patch, SOLR-5476.patch, SOLR-5476.patch
>
>
> In a very large cluster the Overseer is likely to be overloaded.If the same 
> node is a serving a few other shards it can lead to OverSeer getting slowed 
> down due to GC pauses , or simply too much of work  . If the cluster is 
> really large , it is possible to dedicate high end h/w for OverSeers
> It works as a new collection admin command
> command=addrole&role=overseer&node=192.168.1.5:8983_solr
> This results in the creation of a entry in the /roles.json in ZK which would 
> look like the following
> {code:javascript}
> {
> "overseer" : ["192.168.1.5:8983_solr"]
> }
> {code}
> If a node is designated for overseer it gets preference over others when 
> overseer election takes place. If no designated servers are available another 
> random node would become the Overseer.
> Later on, if one of the designated nodes are brought up ,it would take over 
> the Overseer role from the current Overseer to become the Overseer of the 
> system



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