[rrd-users] rrdtool fetch with computed resolution

Sven Ubik ubik at cesnet.cz
Thu Aug 3 12:47:06 MEST 2006


I assume from RRD documentation that it should be possible to fetch
data with arbitrary time resolution (-r argument), not only with one
of time resolutions stored in RRD files, provided that:

   1. both start and end time are a multiple of requested resolution
   2. both start and end time are within the desired RRA

I have RRD file created as:

rrdtool create file.rrd --start 0 --step 1 \
        DS:packets:GAUGE:5:U:U \
        RRA:AVERAGE:0:1:7200 \
        RRA:AVERAGE:0.5:10:17280 \
        RRA:AVERAGE:0.5:60:20160 \
        RRA:AVERAGE:0.5:600:8640 \

That is stored resolutions are 1, 10, 60 and 600 seconds.

When I try to fetch data with 30 second resolution and I think that
both above conditions are met:

rrdtool fetch file.rrd AVERAGE -r 30 -s end-1min -e "11:50 20060803"

then I still get data with 10 second resolution:

1154598550: 1.0851900000e+04
1154598560: 1.0848800000e+04
1154598570: 1.1071000000e+04
1154598580: 1.0682400000e+04
1154598590: 1.0851700000e+04
1154598600: 1.1315900000e+04
1154598610: 1.0789700000e+04

What stored time resolution is used to compute requested time resolution?
Is it the nearest smaller time resolution? Are 10 second averages used to
compute 30 second averages? The implementation is important in order to
decide how much samples of each stored resolution should be kept in RRD

Did you see any error in the commands that I use?

I am using rrdtool 1.2.15.


Sven Ubik

Unsubscribe mailto:rrd-users-request at list.ee.ethz.ch?subject=unsubscribe
Help        mailto:rrd-users-request at list.ee.ethz.ch?subject=help
Archive     http://lists.ee.ethz.ch/rrd-users
WebAdmin    http://lists.ee.ethz.ch/lsg2.cgi

More information about the rrd-users mailing list