[rrd-users] Can't get a graph

[Koenraad Lelong]

Op 03-10-10 13:59, Alex van den Bogaerdt schreef:
...
> It is hard to tell, but it looks as if the data is actually there but
> scaled way down onto the x-axis. If you look at numbers instead of a
> graph it may be easier to see.
> 
> Try to isolate the problem.
> Don't look at the graphs, try rrdtool fetch.
> Don't use fancy ways of specifying time, try to keep it simple.
> You used dump and restore. Good. What happens if you dump the data on
> the new installation and look at it?
> 
> HTH
> Alex
> 
Hi,

Thanks for spotting this. I didn't see that there actually was something
on the graph.

I restored and dumped again, then I see the differences. But I don't
know how to solve this.
This are the first lines of the original dump:
<!-- Round Robin Database Dump --><rrd> <version> 0003 </version>
        <step> 15 </step> <!-- Seconds -->
        <lastupdate> 1286118051 </lastupdate> <!-- 2010-10-03 17:00:51
CEST -->

        <ds>
                <name> PAC </name>
                <type> GAUGE </type>
                <minimal_heartbeat> 30 </minimal_heartbeat>
                <min> 0.0000000000e+00 </min>
                <max> 2.7500000000e+03 </max>

                <!-- PDP Status -->
                <last_ds> 256 </last_ds>
                <value> 1.5360000000e+03 </value>
                <unknown_sec> 0 </unknown_sec>
        </ds>

<!-- Round Robin Archives -->   <rra>
                <cf> MAX </cf>
                <pdp_per_row> 1 </pdp_per_row> <!-- 15 seconds -->

                <params>
                <xff> 5.0000000000e-01 </xff>
                </params>
                <cdp_prep>
                        <ds>
                        <primary_value> 2.5653333333e+02 </primary_value>
                        <secondary_value> NaN </secondary_value>
                        <value> NaN </value>
                        <unknown_datapoints> 0 </unknown_datapoints>
                        </ds>
                </cdp_prep>
                <database>
                        <!-- 2010-10-02 17:01:00 CEST / 1286031660 -->
<row><v> 1.2760000000e+02 </v></row>
                        <!-- 2010-10-02 17:01:15 CEST / 1286031675 -->
<row><v> 1.1920000000e+02 </v></row>
                        <!-- 2010-10-02 17:01:30 CEST / 1286031690 -->
<row><v> 1.0733333333e+02 </v></row>
                        <!-- 2010-10-02 17:01:45 CEST / 1286031705 -->
<row><v> 9.7200000000e+01 </v></row>
                        <!-- 2010-10-02 17:02:00 CEST / 1286031720 -->
<row><v> 9.1733333333e+01 </v></row>
                        <!-- 2010-10-02 17:02:15 CEST / 1286031735 -->
<row><v> 8.5333333333e+01 </v></row>
                        <!-- 2010-10-02 17:02:30 CEST / 1286031750 -->
<row><v> 7.9200000000e+01 </v></row>
                        <!-- 2010-10-02 17:02:45 CEST / 1286031765 -->
<row><v> 7.7133333333e+01 </v></row>
                        <!-- 2010-10-02 17:03:00 CEST / 1286031780 -->
<row><v> 7.3866666667e+01 </v></row>
                        <!-- 2010-10-02 17:03:15 CEST / 1286031795 -->
<row><v> 7.2466666667e+01 </v></row>

I restored this with :
rrdtool restore pv_monitor-20101003.rrd.dump pv_monitor.rrd
And this is what the restored database contains :

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE rrd SYSTEM "http://oss.oetiker.ch/rrdtool/rrdtool.dtd">
<!-- Round Robin Database Dump --><rrd> <version> 0003 </version>
        <step> 15 </step> <!-- Seconds -->
        <lastupdate> 1286118051 </lastupdate> <!-- 2010-10-03 17:00:51
CEST -->

        <ds>
                <name> PAC </name>
                <type> GAUGE </type>
                <minimal_heartbeat> 30 </minimal_heartbeat>
                <min> 0.0000000000e+00 </min>
                <max> 2.0000000000e+00 </max>

                <!-- PDP Status -->
                <last_ds> 256 </last_ds>
                <value> 1.0000000000e+00 </value>
                <unknown_sec> 0 </unknown_sec>
        </ds>

<!-- Round Robin Archives -->   <rra>
                <cf> MAX </cf>
                <pdp_per_row> 1 </pdp_per_row> <!-- 15 seconds -->

                <params>
                <xff> 5.0000000000e+00 </xff>
                </params>
                <cdp_prep>
                        <ds>
                        <primary_value> 2.0000000000e+00 </primary_value>
                        <secondary_value> NaN </secondary_value>
                        <value> NaN </value>
                        <unknown_datapoints> 0 </unknown_datapoints>
                        </ds>
                </cdp_prep>
                <database>
                        <!-- 2010-10-02 17:01:00 CEST / 1286031660 -->
<row><v> 1.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:01:15 CEST / 1286031675 -->
<row><v> 1.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:01:30 CEST / 1286031690 -->
<row><v> 1.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:01:45 CEST / 1286031705 -->
<row><v> 9.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:02:00 CEST / 1286031720 -->
<row><v> 9.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:02:15 CEST / 1286031735 -->
<row><v> 8.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:02:30 CEST / 1286031750 -->
<row><v> 7.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:02:45 CEST / 1286031765 -->
<row><v> 7.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:03:00 CEST / 1286031780 -->
<row><v> 7.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:03:15 CEST / 1286031795 -->
<row><v> 7.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:03:30 CEST / 1286031810 -->
<row><v> 7.0000000000e+00 </v></row>
                        <!-- 2010-10-02 17:03:45 CEST / 1286031825 -->
<row><v> 6.0000000000e+00 </v></row>

A huge difference and it explains the graph. But why is this ?

Thanks for your help.
Regards,
Koenraad Lelong.