[rrd-users] Subtraction and NaN values
eduardo at bragatto.com
Tue Feb 19 17:35:37 CET 2008
Hi there --
I'm using net-snmp to gather some information from a few hundred
servers and I noticed the memBuffer doesn't exist on a few FreeBSD
servers, causing the DS to be filled with NaN values.
The problem occurs when I use memBuffer on a RPN subtraction like this:
Since memBuffer is NaN, memUsedReal is always also NaN for the FreeBSD
servers. If I take "memBuffer,-" out the CDEF line above works flawless.
I've tried to fix it by using IF to change NaN to 0 before the above
CDEF line, thus not causing a problem at the subtraction:
I was expecting memBuffer to have 0 or the value from DSmemBuffer if
it's not NaN.
Does anybody knows what I'm doing wrong?
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