Getting analyzed data from the rrdtool graph

Question

I want to extract hourly data from rrdtool databases to create some graphs in the panel system.

There is no hourly data source in these databases, the closest is a 30-minute data source (they are generated by munin)

Now I can use rrdfetch , but that doesn’t do the nice averaging that rrdgraph will do, so something like this

 rrdtool fetch xxx-apache_accesses-accesses80-d.rrd AVERAGE \ --resolution 3600 -s 1328458200 -e 1328544600 

Can you give me 30 minute data like this

 2012-Feb-05 16:30:00 3.5376357135e+00 2012-Feb-05 17:00:00 3.4655067194e+00 2012-Feb-05 17:30:00 4.0483210375e+00 2012-Feb-05 18:00:00 4.3210061422e+00 .... 

I could average them, but it seems that rrdgraph can output the analyzed text, but I cannot understand the correct spell. Here is what I tried

  rrdtool graph dummy.png -s 1328523300 -e 1328609700 \ DEF:access=xxx-apache_accesses-accesses80-d.rrd:42:AVERAGE \ "PRINT:access:AVERAGE: %5.1lf %S" 

exits

 0x0 4.7 

Now I think it's just the average value for a given period, but is there a way to get rrdtool to spit out the average value for certain pieces or step sizes? I tried --step , but that didn't change the way out.

I could call rrdtool graph for every information I need, but that seems pretty wasteful.

Answer 1

I didn’t have time to publish what I came across the right approach!

 rrdtool xport -s 1328523300 -e 1328609700 --step 3600 \ DEF:access=xxx-apache_accesses-accesses80-d.rrd:42:AVERAGE \ XPORT:access:"average" 

This gives me the dump I need ...

 <?xml version="1.0" encoding="ISO-8859-1"?> <xport> <meta> <start>1328526000</start> <step>3600</step> <end>1328612400</end> <rows>25</rows> <columns>1</columns> <legend> <entry>average</entry> </legend> </meta> <data> <row><t>1328526000</t><v>2.1949556516e+00</v></row> <row><t>1328529600</t><v>2.0074586816e+00</v></row> <row><t>1328533200</t><v>2.4574720485e+00</v></row> <row><t>1328536800</t><v>3.4861890250e+00</v></row> <row><t>1328540400</t><v>4.2725023347e+00</v></row> <row><t>1328544000</t><v>6.2119548259e+00</v></row> <row><t>1328547600</t><v>5.6709432075e+00</v></row> <row><t>1328551200</t><v>6.1214185470e+00</v></row> <row><t>1328554800</t><v>8.1137357347e+00</v></row> <row><t>1328558400</t><v>5.8345894022e+00</v></row> <row><t>1328562000</t><v>6.2264732776e+00</v></row> <row><t>1328565600</t><v>6.1652113350e+00</v></row> <row><t>1328569200</t><v>5.8851025574e+00</v></row> <row><t>1328572800</t><v>5.4612112119e+00</v></row> <row><t>1328576400</t><v>6.3908056120e+00</v></row> <row><t>1328580000</t><v>6.0361776174e+00</v></row> <row><t>1328583600</t><v>6.3164590113e+00</v></row> <row><t>1328587200</t><v>6.0902986521e+00</v></row> <row><t>1328590800</t><v>4.6756445168e+00</v></row> <row><t>1328594400</t><v>3.9461916905e+00</v></row> <row><t>1328598000</t><v>2.9449490046e+00</v></row> <row><t>1328601600</t><v>2.4011760751e+00</v></row> <row><t>1328605200</t><v>2.2187817639e+00</v></row> <row><t>1328608800</t><v>2.1775208736e+00</v></row> <row><t>1328612400</t><v>NaN</v></row> </data> </xport>