[rrd-users] Help - probably a really stupid mistake somewhere ...

[A Darren Dunham]

On Tue, Aug 17, 2010 at 11:23:05AM -0700, Philip Peake wrote:
> The database:
> 
>     rrdtool create test.rrd --start N --step 5 DS:value:GAUGE:5:-1:101
>     RRA:AVERAGE:0.5:1:12
> 
> What I think this does:
> 
>     * Creates a database called test.rrd (it does).
>     * Has a step time of 5 seconds (don't want to wait forever to see data).
>     * Starts from "now".
>     * Has a single data source called "value", which is a GUAGE (keeps
>       the value presented)
>     * Data must be greater than -1 and less than 101
>     * Has a single value stored, which is the AVERAGE of one "record",
>       so will be equivalent to the value stored.

There are some subtleties that you have not described and are easy to
miss.  The RRD will still do normalization.  So data that is inserted
not exactly on a step boundary will affect multiple bins.  It probably
won't be exactly what you're expecting right now. 

Also, I thought that your settings should be sufficient, but I suspect
you need to increase the heartbeat to be greater than 5.  

> Database doesn't seem to be getting the values:
> 
>     $ rrdtool fetch test.rrd AVERAGE -s -30
>                               value
> 
>     1282069345: nan
>     1282069350: nan
>     1282069355: nan
>     1282069360: nan
>     1282069365: nan
>     1282069370: nan
>     1282069375: nan
> 
> 
> I am obviously doing something wrong ... but what???

I get values when increasing the heartbeat.

-- 
Darren