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RE: What does 95th %tile mean?

  • From: David Schwartz
  • Date: Fri Apr 20 02:28:27 2001 
> If you read that page carefully you'll note that he's using a modified
> version of MRTG that doesn't average its samples.  As it says:

	No. The only change he makes the MRTG is to display the 95th percentile
values he computes.

>    This is a patch to add 95th percentile metering to MRTG. This is not as
>    simple a feature as one might think. MRTG normally saves only one day
>    worth of 5-minute samples. It is not possible to accurately
> calculate the
>    95th percentile without having all of the samples for a one
> month period.
>    In order to calculate the 95th percentile for a 30-day period, it is
>    necessary to save an entire 30 days worth of the 5-minute samples.

	Right, so he has to make backups of MRTG's log file in order to have
sufficient history data.

> MRTG does not do that by default, nor does Cricket, nor will any tool
> using RRDtool as an underlying database.

	MRTG does not do *what* by default?

	DS