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https://issues.apache.org/jira/browse/SOLR-8238?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17696260#comment-17696260
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David Smiley commented on SOLR-8238:
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bq. What if the node is out of commission permanently?

Delete the replicas (logically; physically they are already gone); add 
"preferredLeader" to other replicas as appropriate.

bq. How long should one wait ...

Don't!  It's a best-effort thing, not a guarantee.  Initiate async; don't 
block.  Maybe do in a limited pool so as to not do too many at once.

bq. Assume that a node that has preferredleader set for some reason wasn't the 
leader at shutdown, then how do you insure that can become the leader without 
data loss?

Eligibility for leadership requires a replica to be up-to-date which is 
governed by the ZK Shard Terms mechanism that Dat added -- solid engineering 
there!  preferredLeaders is really unrelated; _it cannot make someone a leader 
that isn't otherwise ineligible!_.  Thus no data loss risks in this matter.

Me or one of my esteemed colleagues is likely to re-open this with something.

> Make Solr respect preferredLeader at startup
> --------------------------------------------
>
>                 Key: SOLR-8238
>                 URL: https://issues.apache.org/jira/browse/SOLR-8238
>             Project: Solr
>          Issue Type: Improvement
>          Components: SolrCloud
>    Affects Versions: 5.2.1
>            Reporter: Peter Morgan
>            Priority: Minor
>
> After setting preferredLeader property, noticed that upon restarting leaders 
> revert to wherever they were previously running before REBALANCE was called.  
>  I would expect the preferredLeader to influence the startup election, but it 
> appears it is not observed.



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