RRDTool data source type selection

I have a question related to RRDTool DST. I need to create a database in such a way that even the data is the same (for example, I have six entries per hour with the same value). RRDTool must calculate the AVERAGE of this data.

I'm creating database with following command:

rrdtool create test.rrd --step 15 DS:na:GAUGE:15:0:U RRA:AVERAGE:0.99:1:244 RRA:AVERAGE:0.99:24:244 RRA:AVERAGE:0.99:168:244 RRA:AVERAGE:0.99:672:244 RRA:AVERAGE:0.99:5760:374

And I'm updating database with following command:

rrdtool update test.rrd 1296231519:0.6039

After making 10 entries with the same value (changing timestamp but the same value), I do rrdtool dump test.rrd test.xml, but I don't see any data... It does not contain the 10 entries.

After making 10 entries with a different value (changing timestamp and changing value), I do the dump of database and there are the 10 entries I have done.

What I'm doing wrong? Maybe DST 'GAUGE' is wrong on creation of rrd?

Solution

The data source type is fine, but you have set the update interval to 15 seconds and ALSO set the maximum update interval to 15 seconds ... I would suggest raising to maximum to 30 seconds as you might not be able to provide an update exactly every 15 seconds ...

rrdtool create test.rrd --step 15 \
    DS:na:GAUGE:30:0:U \
    RRA:AVERAGE:0.99:1:244 \
    RRA:AVERAGE:0.99:24:244 \
    RRA:AVERAGE:0.99:168:244 \
    RRA:AVERAGE:0.99:672:244 \
    RRA:AVERAGE:0.99:5760:374

Further your first RRA will keep data for 61 minutes in 15 second intervals, the second one for 144 hours in 6 minute intervals. These seem odd numbers to me ... is this intentional? Maybe have a look at the rrdtool tutorials to see how others approach this.