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https://issues.apache.org/jira/browse/CASSANDRA-1181?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12881733#action_12881733
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Edward Capriolo commented on CASSANDRA-1181:
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I think ThreadPriority will help, however CPU Priority is not directly linked
to IO scheduling. I believe between the the statistics cassandra keeps we could
accomplish something adaptive. Also if we want a solution that is not 100% java
pure we can read /proc/diskstats and use actual disk utilization to be adaptive.
All these methods I suggested fall apart if non-compaction traffic is thrashing
the disk, but if that were the case the node was not healthy in the first place.
> kinder gentler compaction
> -------------------------
>
> Key: CASSANDRA-1181
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1181
> Project: Cassandra
> Issue Type: Task
> Reporter: Jonathan Ellis
> Assignee: Brandon Williams
> Fix For: 0.7
>
> Attachments: CompactionManager.java
>
>
> I suggested this in a ML thread but it seems that nobody actually tried it.
> I think it's worth following up on:
> You could try setting the compaction thread to a lower priority. You could
> add a thread priority to NamedThreadPool, and pass that up from
> CompactionExecutor constructor. According to
> http://www.javamex.com/tutorials/threads/priority_what.shtml you have to run
> as root and add a JVM option to get this to work.
> In particular, Brandon saw stress.py read latencies spike to 100ms during
> [anti]compaction on a 2 core machine. I'd like to see if this can mitigate
> that.
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