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From Harsh J <ha...@cloudera.com>
Subject Re: Why my tests shows Yarn is worse than MRv1 for terasort?
Date Fri, 07 Jun 2013 03:58:12 GMT
Not tuning configurations at all is wrong. YARN uses memory resource
based scheduling and hence MR2 would be requesting 1 GB minimum by
default, causing, on base configs, to max out at 8 (due to 8 GB NM
memory resource config) total containers. Do share your configs as at
this point none of us can tell what it is.

Obviously, it isn't our goal to make MR2 slower for users and to not
care about such things :)

On Fri, Jun 7, 2013 at 8:45 AM, sam liu <samliuhadoop@gmail.com> wrote:
> At the begining, I just want to do a fast comparision of MRv1 and Yarn. But
> they have many differences, and to be fair for comparison I did not tune
> their configurations at all.  So I got above test results. After analyzing
> the test result, no doubt, I will configure them and do comparison again.
> Do you have any idea on current test result? I think, to compare with MRv1,
> Yarn is better on Map phase(teragen test), but worse on Reduce
> phase(terasort test).
> And any detailed suggestions/comments/materials on Yarn performance tunning?
> Thanks!
> 2013/6/7 Marcos Luis Ortiz Valmaseda <marcosluis2186@gmail.com>
>> Why not to tune the configurations?
>> Both frameworks have many areas to tune:
>> - Combiners, Shuffle optimization, Block size, etc
>> 2013/6/6 sam liu <samliuhadoop@gmail.com>
>>> Hi Experts,
>>> We are thinking about whether to use Yarn or not in the near future, and
>>> I ran teragen/terasort on Yarn and MRv1 for comprison.
>>> My env is three nodes cluster, and each node has similar hardware: 2
>>> cpu(4 core), 32 mem. Both Yarn and MRv1 cluster are set on the same env. To
>>> be fair, I did not make any performance tuning on their configurations, but
>>> use the default configuration values.
>>> Before testing, I think Yarn will be much better than MRv1, if they all
>>> use default configuration, because Yarn is a better framework than MRv1.
>>> However, the test result shows some differences:
>>> MRv1: Hadoop-1.1.1
>>> Yarn: Hadoop-2.0.4
>>> (A) Teragen: generate 10 GB data:
>>> - MRv1: 193 sec
>>> - Yarn: 69 sec
>>> Yarn is 2.8 times better than MRv1
>>> (B) Terasort: sort 10 GB data:
>>> - MRv1: 451 sec
>>> - Yarn: 1136 sec
>>> Yarn is 2.5 times worse than MRv1
>>> After a fast analysis, I think the direct cause might be that Yarn is
>>> much faster than MRv1 on Map phase, but much worse on Reduce phase.
>>> Here I have two questions:
>>> - Why my tests shows Yarn is worse than MRv1 for terasort?
>>> - What's the stratage for tuning Yarn performance? Is any materials?
>>> Thanks!
>> --
>> Marcos Ortiz Valmaseda
>> Product Manager at PDVSA
>> http://about.me/marcosortiz

Harsh J

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