[hobbit] Re: Custom RRD graphs

[Dan Vande More]

On 11/12/05, Rich Smrcina <rsmrcina at wi.rr.com> wrote:
> Brilliant detective work Dan.  I am trying something similar, but
> haven't had the good luck that you enjoy.
I am a very bad C coder. I'd call it luck too.:)

>
> Here is the status message being produced for a column called pg_util
> (Page Utilization):
>
> status vm1.pg_util green 12 Nov 2005 10:55:57  Page Utilization  OK
> pg_util : 1
>
>
> z/VM Version 4 Release 4.0, service level 0402 (32-bit)
>              EXTENT EXTENT  TOTAL  PAGES   HIGH    %
> VOLID  RDEV  START    END  PAGES IN USE   PAGE USED
> ------ ---- ------ ------ ------ ------ ------ ----
> 440RES 0124    257    390  24120    529    559   2%
> PAGSP1 0102    301   3338 546840      0      0   0%
>                            ------ ------        ----
> SUMMARY                   570960    529          1%
> USABLE                    570960    529          1%
>
Looks good;)
> TEST2RRD contains 'pg_util=ncv' (it's not at the end, does it need to
> be?) and
Nope, shouldn't matter where it is.
>
> NCV_pg_util="pg_util:GAUGE"
>
> I've disabled the code in the extra script for this test and removed it
> from the --extra-tests list.  I've verified with ps that hobbitd_channel
> and hobbitd_larrd aren't using them anymore.  I still have a custom
> graph defined for this test, is that allowed using NCV or doesn't it care?
>
Custom graphing (with ncv) is really a two step process. The first and
most important is collecting the data into an rrd, which is simple and
done by adding your COLUMNNAME=ncv to TEST2RRD and correctly passing
data back to hobbit:)
I used "rrdtool dump foo.rrd > tmp.xml" to verify that it was actually
collecting some data.

I would venture to guess that as long as your test/column names stay
the same, there will be no problems in switching from --extra-tests to
ncv.

The second step, of course, is actually graphing it using data from
the rrd. I found this to be the most difficult step, if only because I
skim documentation - I don't read unless I'm desperate. Again, I'm
going out on a limb to say as long as your datasources/testnames/Y
values are all the same, your graph configuration should work post-ncv
conversion.

Good luck

Dan