[rrd-users] What's the best way?

DEIGNAN Ciaran C.DEIGNAN at rsd.com
Tue Mar 15 11:49:39 CET 2016

Hi Alex,

> > I thought initially that since the number of requests and the number of
> > bytes are both converted to rates, I could simply graph a CDEF of
> > (bytes/requests).
> > I tried that and it doesn't look good.
> And what exactly looks wrong?
> You have bytes per second: B/s and requests per second: R/s.  When you
> divide those, the math should look like: B/s / R/s = B/s * s/R = B/R.
> To get you started, doing this from memory without any checking:
> DEF:bps {get your bytes per second from total bytes transfered}
> DEF:rps {get your requests per second from total number of requests}
> CDEF:bpr=bps,rps,0,EQ,1,rps,IF,/
> That CDEF can be read as:  if (rps==0) bpr=bps/1 else bpr=bps/rps.

That was my initial plan but my standalone tests weren't good.
I now have a more valid environment and your formula gives me good results.

I didn't like the idea of preprocessing the data before giving it to RRD, it just feels wrong.

Thanks again,

Ciaran Deignan
RSD Open Systems Support

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