[ On Friday, April 20, 2001 at 00:52:39 (-0400), Charles Sprickman wrote: ]
Subject: RE: What does 95th %tile mean?
On Thu, 19 Apr 2001, Greg A. Woods wrote:
Neither MRTG nor Cricket (nor anything with RRDtool or anything similar underlying it), in their standard released form, are truly suitable for accounting purposes since they both can introduce additional averaging errors. You need to keep all of the original sample data.
This actually works pretty well:
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: 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. MRTG does not do that by default, nor does Cricket, nor will any tool using RRDtool as an underlying database.
There was a very similar discussion just weeks ago on the datacenter mailinglist as well, you all might want to peek at the archives...
Perhaps you should look again at who posted to that discussion.... :-) -- Greg A. Woods +1 416 218-0098 VE3TCP <gwoods@acm.org> <woods@robohack.ca> Planix, Inc. <woods@planix.com>; Secrets of the Weird <woods@weird.com>