[rrd-users] Short step records NaN

Jaro Lepis jarolepis at gmail.com
Sun Mar 2 09:28:52 CET 2008


Hi ,
I am trying to figure out how to get my data in without showing mostly NaNs.
Below is smal sample of what I am trying to do and what I get.

rrdtool create /data/test.rrd             \
            --start 1204393441          \
            --step 3 \
            DS:speed:GAUGE:6:U:U   \
            RRA:AVERAGE:0.5:1:10

rrdtool update /data/test.rrd 1204393447:2331
rrdtool update /data/test.rrd 1204393451:2676
rrdtool update /data/test.rrd 1204393454:2985
rrdtool update /data/test.rrd 1204393458:3346
rrdtool update /data/test.rrd 1204393461:3730
rrdtool update /data/test.rrd 1204393465:3957
rrdtool update /data/test.rrd 1204393468:4172
rrdtool update /data/test.rrd 1204393472:4352
rrdtool update /data/test.rrd 1204393476:4629
rrdtool update /data/test.rrd 1204393479:4901

<!-- Round Robin Database Dump --><rrd> <version> 0003 </version>
        <step> 3 </step> <!-- Seconds -->
        <lastupdate> 1204393479 </lastupdate> <!-- 2008-03-01 09:44:39 PST -->

        <ds>
                <name> speed </name>
                <type> GAUGE </type>
                <minimal_heartbeat> 6 </minimal_heartbeat>
                <min> NaN </min>
                <max> NaN </max>

                <!-- PDP Status -->
                <last_ds> UNKN </last_ds>
                <value> 0.0000000000e+00 </value>
                <unknown_sec> 0 </unknown_sec>
        </ds>

<!-- Round Robin Archives -->   <rra>
                <cf> AVERAGE </cf>
                <pdp_per_row> 1 </pdp_per_row> <!-- 3 seconds -->

                <params>
                <xff> 5.0000000000e-01 </xff>
                </params>
                <cdp_prep>
                        <ds>
                        <primary_value> 4.9010000000e+03 </primary_value>
                        <secondary_value> 4.5366666667e+03 </secondary_value>
                        <value> NaN </value>
                        <unknown_datapoints> 0 </unknown_datapoints>
                        </ds>
                </cdp_prep>
                <database>
                        <!-- 2008-03-01 09:44:12 PST / 1204393452 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:15 PST / 1204393455 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:18 PST / 1204393458 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:21 PST / 1204393461 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:24 PST / 1204393464 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:27 PST / 1204393467 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:30 PST / 1204393470 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:33 PST / 1204393473 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:36 PST / 1204393476 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:39 PST / 1204393479 -->
<row><v> 4.9010000000e+03 </v></row>
                </database>
        </rra>
</rrd>



When I chage .rrd a little by going from 10 row to 21 and feeding in
same dataset I get:

   rrdtool create /data/test.rrd             \
            --start 1204393441          \
            --step 3 \
            DS:speed:GAUGE:6:U:U   \
            RRA:AVERAGE:0.5:1:21

<!-- Round Robin Database Dump --><rrd> <version> 0003 </version>
        <step> 3 </step> <!-- Seconds -->
        <lastupdate> 1204393479 </lastupdate> <!-- 2008-03-01 09:44:39 PST -->

        <ds>
                <name> speed </name>
                <type> GAUGE </type>
                <minimal_heartbeat> 6 </minimal_heartbeat>
                <min> NaN </min>
                <max> NaN </max>

                <!-- PDP Status -->
                <last_ds> UNKN </last_ds>
                <value> 0.0000000000e+00 </value>
                <unknown_sec> 0 </unknown_sec>
        </ds>


<!-- Round Robin Archives -->   <rra>
                <cf> AVERAGE </cf>
                <pdp_per_row> 1 </pdp_per_row> <!-- 3 seconds -->

                <params>
                <xff> 5.0000000000e-01 </xff>
                </params>
                <cdp_prep>
                        <ds>
                        <primary_value> 4.9010000000e+03 </primary_value>
                        <secondary_value> 4.5366666667e+03 </secondary_value>
                        <value> NaN </value>
                        <unknown_datapoints> 0 </unknown_datapoints>
                        </ds>
                </cdp_prep>
                <database>
                        <!-- 2008-03-01 09:43:39 PST / 1204393419 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:43:42 PST / 1204393422 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:43:45 PST / 1204393425 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:43:48 PST / 1204393428 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:43:51 PST / 1204393431 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:43:54 PST / 1204393434 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:43:57 PST / 1204393437 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:00 PST / 1204393440 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:03 PST / 1204393443 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:06 PST / 1204393446 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:09 PST / 1204393449 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:12 PST / 1204393452 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:15 PST / 1204393455 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:18 PST / 1204393458 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:21 PST / 1204393461 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:24 PST / 1204393464 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:27 PST / 1204393467 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:30 PST / 1204393470 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:33 PST / 1204393473 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:36 PST / 1204393476 -->
<row><v> NaN </v></row>
                        <!-- 2008-03-01 09:44:39 PST / 1204393479 -->
<row><v> 4.9010000000e+03 </v></row>
                </database>
        </rra>
</rrd>

Also I noticed that in second case first row of .rrd has timestamp
smaller than start point set in .rrd creation file:
rrdtool create /data/test.rrd --start 1204393441
...
<database>
            <!-- 2008-03-01 09:43:39 PST / 1204393419 --> <row><v> NaN
</v></row>

I can not explain or figure out none of the above.
I am trying to store values for short total runtime (up to 3 hours)
arriving in inconsistent 3to5 sec frequency (--step 3).
Is that possible do do?

thank you
jaro



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