Hi Lejf, ABSOLUTE, like DERIVED and COUNTER, are used for things that DO have a relation to time. To make an example related to your memory graphs, consider page swaps: The values for these are always in the context of your polling frequency, e.g 'x page-outs in the last 300s'. Now you COULD display these using a gauge and your graph would display the total number of swaps per polling interval. However, from a sysadmin point of view, it's much more interesting to know the rate, i.e. page-out/s. Hence you'd use one of the counters ABSOLUTE, DERIVED AND COUNTER, which of these depends on the type of counter you get your values from *.
ABSOLUTE is for counters that are reset with every read. The other two are fundamentally the same: they are used for continous counters where the value for a given period is current value - previous value. The difference is in the way they handle counter overflows. cheers -stefan *) In the interest of full disclosure: For the image, you can convert between rates and total values by graphing a CDEF that multiplies/divides the DEF by the polling period, instead of graphing the DEF directly. But it usually makes more sense to just choose the right DS type when creating the RRD. Lejf Diecks wrote: > Stefan Moser <[EMAIL PROTECTED]> wrote: > >> For stuff like that you use DS type GAUGE, not absolute. [..] >> a metric like memory free "is not really connected with a >> time". Hence you use GAUGE as a datatype. > > Hi Stefan, > > changing from ABSOLUTE to GAUGE works perfectly! I wonder what ABSOLUTE is > good for? > > Anyway, thank you a lot! > > Lejf -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://lists.ee.ethz.ch/rrd-users WebAdmin http://lists.ee.ethz.ch/lsg2.cgi
