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From Christopher <>
Subject Re: Question about configuring the linux niceness of tablet servers?
Date Mon, 17 Aug 2015 23:15:14 GMT
I haven't heard of anybody setting the niceness of the Accumulo
processes before. Are you experiencing a lot of CPU contention on your
nodes, such that you need to prioritize processes?

However, if you do this, I think you actually want HDFS to -2,
Accumulo to -1, and Mapreduce tasks 0 (you'll have to edit the system
security limits to allow niceness below 0 for non-root users).
Otherwise, you're lowering the priority, not increasing it (and
lowering it below other, normal user processes, since the default
niceness is 0).

Christopher L Tubbs II

On Mon, Aug 17, 2015 at 5:21 PM, Jeff Kubina <> wrote:
> On each of the processing nodes in our cluster we have running 1) HDFS
> (datanode), 2) Accumulo (tablet server), and 3) Hadoop. Since Accumulo
> depends on the HDFS, and Hadoop depends on the HDFS and sometimes on
> Accumulo, we are considering setting the niceness of HDFS to 0 (the current
> value), Accumulo to 1, and Hadoop to 2 on each of the nodes. The objective
> is to improve the real time performance of Accumulo.
> Does anyone have experience configuring their cluster in a similar manner
> that they can share?  Are there any serious cons to doing this?

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