[rrd-users] rrdtool memory usage and the Raspberry Pi

[Simon Hobson]

Rafal Gwizdala <rafal.gwizdala at gmail.com> wrote:

> Maybe the file size growth is expected to be parabolic - i think every RRA is 'global' - it covers all the data sources. So when you're adding DS and RRA pair you're actually adding N RRAs where N is number of data sources. At least this is how i understood the concept of RRAs.

Yes, that is correct - each RRA applied to every DS in the file. File size will scale (roughly) as D*R where D is number of data sources, and R is number of RRAs.



> [08:32:57 pe at hope] $ rrdtool create test.rrd \
> > --step 1s \
> > DS:progreset:GAUGE:1000s:0:1 RRA:MAX:0.1:5s:5000m \
> > DS:tpm:GAUGE:1000s:0:1 RRA:LAST:0.1:5s:5000m \
> > DS:voltcontrol:GAUGE:1000s:0:1 RRA:LAST:0.1:5s:5000m \

Duplicate RRA

> > DS:freqcontrol:GAUGE:1000s:0:1 RRA:LAST:0.1:5s:5000m \

Another duplicate

> > DS:fault:GAUGE:1000s:0:1 RRA:MAX:0.1:5s:5000m \
> > DS:uff:GAUGE:1000s:0:1 RRA:MAX:0.1:5s:5000m \
> > DS:off:GAUGE:1000s:0:1 RRA:MAX:0.1:5s:5000m \
> > DS:uvf:GAUGE:1000s:0:1 RRA:MAX:0.1:5s:5000m \
> > DS:ovf:GAUGE:1000s:0:1 RRA:MAX:0.1:5s:5000m \

5 more duplicates

> > DS:svopen:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:svclose:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:bvopen:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:bvclose:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:syncen:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:busconnen:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:wmfull:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:wmmed:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:wmlow:GAUGE:1000s:0:1 RRA:AVERAGE:0.1:5s:5000m \
> > DS:vred:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:exciter:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:ired:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:iwhite:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:iblue:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:f:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:isp:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:dlred:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:dlwhite:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:dlblue:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m \
> > DS:svpos:GAUGE:1000s:0:32000 RRA:AVERAGE:0.1:5s:5000m

Another 19 duplicates


As a matter of style, I always put my RRAs at the end - so I have some "header" stuff, then a list of DSs, then a list of RRAs. Makes it much easier to read.
As an aside, does it matter what order they are declared in ? Ie, if an RRA is declared before all the DSs, does it still apply to all DSs ? I would hope so.