[rrd-users] RRD smoothing - please help

[William R. Lorenz]

Hej Johan,

On Mon, 10 Nov 2008, johan thoren wrote:

> Im trying to figure out how to configure the RRD tool. My goal is to 
> store data and ONLY display the maximum value. At a heart beat rate of 
> 100 I store into RRD for a 300 time interval. See my rrd definition

> DS:sPHI:GAUGE:100:0:1000
> RRA:MAX:0.1:18:1000

> The values I get are typically 1,2,3,4 and NEVER any digits

In general, your heartbeat interval should be set greater than the 
interval at which you store data.  In example, if you store data to your 
RRD file every 300 seconds, you may consider setting your heartbeat 
interval for 600 seconds (or even 3600 seconds, which is much larger).

> Why I gods name will RRDtool approximate and display graph- values like 
> 1.3, 0.7, 2.2... This to me does not look like a TRUE maxiumum value, 
> but instead only an AVERAGE value...

Your maximum value, for starters, will be largely effected by the 
frequency/resolution at which you run your data collection.  So, if you're 
only sampling your data every 300 seconds, you'll only get one reading for 
that period, not necessarily the maximum value over that period of time.
Someone else with more rrdtool experience can correct me if I'm mistaken.

> Is there any way to get thsi basic functionality to work or am I forced 
> to look for another software then the RRDtool???

Your best bet is to kindly :-) share more information about what you're 
trying to accomplish and the specific application surrounding your use of 
rrdtool.  That might encourage more help/insights from the mailing list.

Hope this helps.  Ha det så bra!

-- 
William R. Lorenz