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From Philippe <watche...@gmail.com>
Subject Re: Different Load values after stress test runs....
Date Tue, 23 Aug 2011 16:11:04 GMT
Have you run repair on the nodes ? Maybe some data was lost and not repaired
yet ?

Philippe

2011/8/23 Chris Marino <chris@vcider.com>

> Hi, we're running some performance tests against some clusters and I'm
> curious about some of the numbers I see.
>
> I'm running the stress test against two identically configured clusters,
> but after I run at stress test, I get different Load values across the
> clusters?
>
> The difference between the two clusters is that one uses standard EC2
> interfaces, but the other runs on a virtual network. Are these differences
> indicating something that I should be aware of??
>
> Here is a sample of the kinds of results I'm seeing.
>
> Address         DC          Rack        Status State   Load            Owns
>    Token
>
>                                  12760588759xxx
> 10.0.0.17       DC1         RAC1        Up     Normal  94 MB
> 25.00%  0
> 10.0.0.18       DC1         RAC1        Up     Normal  104.52 MB
> 25.00%  42535295865xxx
> 10.0.0.19       DC1         RAC1        Up     Normal  78.58 MB
>  25.00%  85070591730xxx
> 10.0.0.20       DC1         RAC1        Up     Normal  78.58 MB
>  25.00%  12760588759xxx
>
> Address         DC          Rack        Status State   Load            Owns
>    Token
>
>                                     12760588759xxx
> 10.120.35.52    DC1         RAC1        Up     Normal  103.74 MB
> 25.00%  0
> 10.120.6.124    DC1         RAC1        Up     Normal  118.99 MB
> 25.00%  42535295865xxx
> 10.127.90.142   DC1         RAC1        Up     Normal  104.26 MB
> 25.00%  85070591730xxx
> 10.94.69.237    DC1         RAC1        Up     Normal  75.74 MB
>  25.00%  12760588759xxx
>
> The first cluster with the vNet (10.0.0.0/28 addresses) consistently show
> smaller Load values. The total Load of 355MB vs. 402MB with native EC2
> interfaces?? Is a total Load value even meaningful?? The stress test is the
> very first thing that's run against the clusters.
>
> [I'm also a little puzzled that these numbers are not uniform within the
> clusters, but I suspect that's because the stress test is using a key
> distribution that is Gaussian.  I'm not 100% sure of this either since I've
> seen conflicting documentation. Haven't tried 'random' keys, but I presume
> that would change them to be uniform]
>
> Except for these curious Load numbers, things seem to be running just fine.
> Getting good fast results. Over 10 iterations I'm getting more than 10-12K
> inserts per sec. (default values for the stress test).
>
> Should I expect the Load to be the same across different clusters?? What
> might explain the differences I'm seeing???
>
> Thanks in advance.
> CM
>

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