You misunderstood. I am trying to get at means by which I can graph "expressions of the type guage" which are constructed using "MIB objects that are counters".
I KNOW MRTG has the functionality to calculate percent utilization for "network interfaces". I just illustrated with my "fictitious" instance where the aim was: I was trying to calculate/graph percent network utilization using my custom formula, but didn't exactly know how to instruct MRTG/RRD to do it - given that MRTG allows only guage or counter types for expressions - neither of which are valid. I know that. The aim is NOT to calculate any rate over an unknown time, rather the aim of this fictitious example is to calculate % network utilization since the time the value was last acquired. Can you suggest an MRTG expression and type to do it? Mohit -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of PAUL WILLIAMSON Sent: Thursday, September 08, 2005 1:45 PM To: [EMAIL PROTECTED] Subject: [mrtg] Re: Counter Or Gauge >>> "Tendolkar Mohit" <[EMAIL PROTECTED]> 09/08/05 3:57 PM >>> > Hi, > <snip> > ((ifInOctets[ifIndex] + ifOutOctets[ifIndex]) * 8 / > ifSpeed[ifIndex]) * 100 So, this looks like the percentage utilization in bits per second... > But unfortunately, both ifInOctest and ifOutOctets are MIB counter > objects (their values keep increasing). You are trying to replace the functionality inherent in MRTG to calculate the rate over time, but expressed as a percentage utilized over an unknown period of time. What you are trying to do makes really no sense. > So although the resultant value of this expression should be a guage > (because percent utilization for the interface keeps incrementing and > decrementing), I have to set the type for this target expression as an > MRTG counter. True, because you are trying to graph a number that really doesn't mean anything. > But still it is incorrect, because when I label the expression as an > MRTG/RRD counter, MRTG/RRD tracks the value as a "RATE" (difference in > seconds) : which again makes the value being graphed incorrect. But you have a base assumption that the number you are attempting to graph makes any sense. From your example, it does not. > So how do you suggest I graph such expressions using MRTG or RRD, > which have MIB counter objects, but the resultant values from the > expression itself is NOT a rate? Normally, this would be expressed as a GAUGE. But because you are trying to graph the TOTAL octets passed through an interface since either a) restart or b) rollover, they really don't mean anything. Let's take the following literal example based off your example, without regard to poll cycle... MaxBytes: 500 Poll 0: 0 + 0 = 0 (start of system) Poll 1: 50 + 50 = 100 (20%) Poll 2: 75 + 100 = 175 (15%) Poll 3: 200 + 125 = 325 (30%) Poll 4: 250 + 175 = 425 (20%) I'm sure Alex will be able to demonstrate this with specifics, but if you try to figure out anything other than the 5 minute utilization (via bps or %), there is not much more to gain. I may just not be getting what you are trying to accomplish, but it seems like you either want an ever increasing percentage, or a static counter, neither of which really do what you want. If you use the unscaled option, it will give you a visual representation of % utilization without having a 0-100% numbered scale on the y-axis. Paul -- Unsubscribe mailto:[EMAIL PROTECTED] Archive http://lists.ee.ethz.ch/mrtg FAQ http://faq.mrtg.org Homepage http://www.mrtg.org WebAdmin http://lists.ee.ethz.ch/lsg2.cgi -- Unsubscribe mailto:[EMAIL PROTECTED] Archive http://lists.ee.ethz.ch/mrtg FAQ http://faq.mrtg.org Homepage http://www.mrtg.org WebAdmin http://lists.ee.ethz.ch/lsg2.cgi
