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Date: Wed, 16 Apr 2014 14:30:23 +0000 (UTC)
From: "Jonathan Ellis (JIRA)" <jira@apache.org>
To: commits@cassandra.apache.org
Message-ID: <JIRA.12630778.1360019633971.124938.1397658623379@arcas>
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Subject: [jira] [Commented] (CASSANDRA-5220) Repair improvements when using
 vnodes
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    [ https://issues.apache.org/jira/browse/CASSANDRA-5220?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13971465#comment-13971465 ] 

Jonathan Ellis commented on CASSANDRA-5220:
-------------------------------------------

I just talked to some people who were seeing an 8 node (256 vnodes each) repair with about 1GB/node take *two days*.

I would suggest doing some more digging to see where all the overhead is coming from, before guessing at solutions.

> Repair improvements when using vnodes
> -------------------------------------
>
>                 Key: CASSANDRA-5220
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5220
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>    Affects Versions: 1.2.0 beta 1
>            Reporter: Brandon Williams
>            Assignee: Yuki Morishita
>              Labels: performance, repair
>             Fix For: 2.1 beta2
>
>
> Currently when using vnodes, repair takes much longer to complete than without them.  This appears at least in part because it's using a session per range and processing them sequentially.  This generates a lot of log spam with vnodes, and while being gentler and lighter on hard disk deployments, ssd-based deployments would often prefer that repair be as fast as possible.


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