[rrd-users] rrdupdate problem

[Alex van den Bogaerdt]

On Thu, Nov 22, 2007 at 04:34:20PM +0100, Andras Dosztal wrote:

> I have a problem updating my rrd files. My script should do the following:
> 1. Separate data from a raw file to variables

Debug these variables.

> 2. Update the rrd files (create them, if they don't exist) in every 10
> minutes. The filename is <MAC_address>.rrd

See comments below

> 3. Make some graphs.

but not when a new database was created. No problem though.

> The problem is that after updating, the rrd file contains only NaN
> values. I get no errors when running the script.

After updating in general, or only after the first update?

> #!/bin/bash
> 
> OUTDIR="/srv/www/htdocs/rrd"
> WORKDIR="${HOME}/rrd"
> 
> RAW=`cat $WORKDIR/raw.dat`
> for i in $RAW
> do

[snip: get vars]

> if [ -s ${MAC}.rrd ]; then
> 	rrdtool update ${WORKDIR}/${MAC}.rrd
> N:${U_RX}:${U_SNR}:${M_TX}:${M_SNR}:${M_RX}

no problem here. However, it would make sense to use an
absolute timstamp instead of "N", this also makes debugging possible
when you write the rrdtool update command to a log file for future
reference.

[snip: create graphs]
> 
> else

> 	rrdtool create ${WORKDIR}/${MAC}.rrd \
>         --step 600 \
>         --start now \

Start is 'now'.

>         DS:u_rx:GAUGE:1200:U:U \
>         DS:u_snr:GAUGE:1200:0:U \
>         DS:m_tx:GAUGE:1200:0:U \
>         DS:m_snr:GAUGE:1200:0:U \
>         DS:m_rx:GAUGE:1200:U:U \
>         RRA:LAST:0.5:1:144 \
>         RRA:AVERAGE:0.5:6:168 \
>         RRA:AVERAGE:0.5:144:31 \
> 	RRA:AVERAGE:0.5:1008:52
> 
> 	rrdtool update ${WORKDIR}/${MAC}.rrd
> N:${U_RX}:${U_SNR}:${M_TX}:${M_SNR}:${M_RX}
> fi

Update is also 'now'.  It is highly likely that you do not fill an
entire RRA-step.  See my site, the part about normalization and
consolidation. 


-- 
Alex van den Bogaerdt
http://www.vandenbogaerdt.nl/rrdtool/