DragonFly On-Line Manual Pages
Smokeping::matchers::Medratio - detect changes in the latency median
The Medratio matcher establishes a historic median latency over several
measurement rounds. It compares this median, against a second median
latency value again build over several rounds of measurement.
By looking at the median value this matcher is largly imune against
spikes and will only react to long term developments.
Call the matcher with the following sequence:
type = matcher
pattern = Medratio(historic=>a,current=>b,comparator=>o,percentage=>p)
The number of values to use for building the 'historic' median.
The number of values to use for building the 'current' median.
Which comparison operator should be used to compare
current/historic with percentage.
Right hand side of the comparison.
old <--- historic ---><--- current ---> now
Take the 12 last median values. Build the median out of the first 10
and the median from the other 2 values. Divide the results and decide
if it is bigger than 150 percent.
med(current)/med(historic) > 150/100
This means the matcher will activate when the current latency median is
more than 1.5 times the historic latency median established over the
last 10 rounds of measurement.
Copyright (c) 2006 by OETIKER+PARTNER AG. All rights reserved.
The development of this matcher has been paied for by Virtela
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
675 Mass Ave, Cambridge, MA 02139, USA.
Tobias Oetiker <email@example.com>