[rrd-users] How to add up traffic logged with DERIVE?
rrdtool at vadim.ws
Thu Jul 3 15:25:55 CEST 2008
I've got a "wireless Internet" 3G modem. I want to generate bandwidth usage
graphs with projections of how long it will take to reach my bandwidth limit
at the current rate.
I went with a DERIVE counter, because I'm tracking traffic on the ppp0
interface, which appears and disappears often (multiple times per day), which
resets the count. Also I want to be able to begin summing from any arbitrary
I want to take this DERIVE counter, and add up all the values up to each point
on the graph. Ideally, I also want to force the counter to 0 at the start of
a month, if possible.
Unfortunately, all attempts so far have been unsuccessful. RRD doesn't seem to
let me reference a CDEF in itself. My first approach
was: "CDEF:acc_rx=acc_rx,rx,+". This produces an "invalid RPN expression".
Trying "CDEF:acc_rx=rx,TOTAL" doesn't work either, since TOTAL only works for
VDEFs. TOTAL is nearly what I want to get, if I give up on the zeroing the
count on the start of the month.
Is there a way to get this done?
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