I think it is what was called 'reverse Polish notation' when I was in
highschool. Here are some
examples that I use regularly. Note the destinction between \ continuation
and / division. Don't
leave any blanks after the continuations. Check snmpCol.trace after
changing it. It will report
any errors. Be sure to leave a '.' at the end of the variables that will
have interface indices
appended. I also use entries here to reverse the direction (mib -1 *) to
deal with the
increase-only thresholding in snmpcollect. The format is
label
description - explain the formula here for when you forget
formula
Thepost-fix notation formula requires operand, operand, operator. So the
first one reads like this:
inoctets outoctets + # adds in and out
octets
(preceding sum) 8 * # multiplies the sum
by 8
(preceding product) 100 * # multiplies the product by
100
(preceding product ) ifspeed / # divides the preceding
product by the ifspeed
==============================================
Expression in /usr/OV/conf/mibExpr.conf
(from Glenn Aikens)
For lans, measure both send and receive, since data only flows in one
direction at a time (half-duplex):
LANIf%Util \
"% interface utilization from \
((ifInOctets + ifOutOctets) * 8 * 100) / ifSpeed" \
.1.3.6.1.2.1.2.2.1.10.
\
.1.3.6.1.2.1.2.2.1.16. +
\
8 * 100 *
\
.1.3.6.1.2.1.2.2.1.5. /
For WANs, measure separately, since data flows both ways at once
(full-duplex):
WANIf%RecvUtil \
"% interface utilization from \
(ifInOctets * 8 * 100) / ifSpeed" \
.1.3.6.1.2.1.2.2.1.10. \
8 * 100 *
\
.1.3.6.1.2.1.2.2.1.5. /
WANIf%SendUtil \
"% interface utilization from \
(ifOutOctets * 8 * 100) / ifSpeed" \
.1.3.6.1.2.1.2.2.1.16. \
8 * 100 *
\
.1.3.6.1.2.1.2.2.1.5. /
Glenn Aikens explanation of what to use when for WANs:
A 56kb line can send 56kb and receive 56kb at the same time. So in one
sense its capacity is 112kb, but not really, since neither can use more
than 56kb. Two methods:
1) Take the highest: util = max(wansend,wanrecv)
This tells you how close you are to the limit, regardless of the
direction that is being a pig.
2) Take the average or double the speed:
util=8*(inoctets+outoctets)/(ifspeed*2)*100
This gives effective util of entire link, but is deceptive about how
close you are to capacity. Eg 99% send and 21% receive would show as
60% util, but you are really maxxed on the send side.
Cordially,
Leslie A. Clark
IBM Global Services - Systems Mgmt & Networking
Howdy,
does anyone have some good examples of working expressions you may
have put together, I am struggling with the placement of my operators in
the expressions I am creating in mibExpr.conf
I'm trying something pretty simple really, just attempting a (mibvar * 8)
/ mibvar /100 type of scenario and for some reason I'm getting out of this
world figures.
Thanks
Mark
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