[rrd-users] problem with lost of data, file size always the same!

[Francesco Andreozzi]

Hi all, this is my first post and i hope to be clear :D

i have start to using rrd because seems to be really nice stuff....

i create a lot of rrd to collect data from a specific device ...

i create an rrd with the command like this

rrdtool create <RRDNAME.rrd> --start <my-date> \
         DS:<my-obj>:GAUGE:<my-time>0:U \
         RRA:MIN:0.5:12:1440 \
         RRA:MAX:0.5:12:1440 \
         RRA:AVERAGE:0.5:1:1440

the collection seems to be good except i'm lost some data!!!...

if i do a rrdtool dump I can see min and max value from the starting  
time, but avarage no, the first values are lost every 5 minutes, when  
i do the rrdtool update!

the file size is always the same and it doesn't increase!

when i'm creating graph i really want to use avarage values! but on  
this way i think i will gona lost all this information!

please help me.
and ask if you need more infos to help me.

Ciao
Francesco