[rrd-users] RRA

[Simon Hobson]

fadwa salam wrote:

>I want to do a loop to create RAR archives by varying each time 
>pdp_per_row and number of records that will be given as arguments.
>
>    rrdtool create $ rrd \
>              - start $ now \
>              - step = $ step \
>              DS: Power: GAUGE: 600: U: U
>              RRA: AVERAGE: 0.5: $ pdp $ nb
>
>The problem is that I can not handle RAR alone. They are linked to 
>the process of the creation.
>
>if I put the whole process of creation inside the loop ,it create a 
>single RAR archive and take the last value.

If I understand this correctly, you want build up an RRA piecemeal - 
create the basic file and then add RRAs to it one by one.

This is not supported by RRD, you are expected to build it in one go 
- like this :

   rrdtool create $ rrd \
     - start $ now \
     - step = $ step \
     DS: Power: GAUGE: 600: U: U
     RRA: AVERAGE: 0.5: $pdp1 $nb1
     RRA: AVERAGE: 0.5: $pdp2 $nb2
     RRA: AVERAGE: 0.5: $pdp3 $nb3

Whilst there are tools for adjusting RRD files, I don't think it 
would be easy (or even possible ?) to do what you want with them.

Possibly your best approach would be to make a "wrapper script" to 
consolidate the steps and then make one call to create the RRD file. 
Something along these lines :

cmd_text="- start $ now \
     - step = $ step \
     DS: Power: GAUGE: 600: U: U \
"

while <some condition> do
   <get consolidation>
   cmd_text=`echo "${cmd_text} RRA:${cf_func}:${hb}:${pdp}:{nb} \
"`
done
rrdtool create $ rrd ${cmd_text}

-- 
Simon Hobson

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