How do you (not how do I) calculate 95th percentile?

Warren Kumari warren at kumari.net
Wed Feb 22 19:28:44 UTC 2006


On Feb 22, 2006, at 10:12 AM, Jo Rhett wrote:


>
> A lot of smaller folks check the counter every 5 min and use that same
> value for the 95th percentile.  Most of us larger folks need to  
> check more
> often to prevent 32bit counters from rolling over too often.  Are  
> you larger
> folks averaging the retrieved values over a larger period?  Using the
> maximum within a larger period?  Or just using your saved values?

Most people are using 64 bit counters. This avoids the wrapping  
problem (assuming you don't have 100GE and poll more then once every  
5 years :-)).
>
> This is curiosity only.  A few years ago we compared the same data  
> and the
> answers varied wildly.  It would appear from my latest check that  
> it is
> becoming more standardized on 5-minute averages, so I'm asking here  
> on Nanog
> as a reality check.

Yup, 5 min seems to be the accepted time.
>
> Note: I have AboveNet, Savvis, Verio, etc calculations.  I'm wondering
> if there are any other odd combinations out there.
>
> Reply to me offlist.  If there is interest I'll summarize the results
> without identifying the source.
>
> -- 
> Jo Rhett
> senior geek
> SVcolo : Silicon Valley Colocation
>




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