[rrd-users] Re: Adding "0" instead of nothing when there's no data

Rejo Zenger subs-rrd-users at sisterray.xs4all.nl
Thu Sep 19 21:18:18 MEST 2002


Hi,

First of all thanks a lot for your time and patience. I guess the whole
concept isn't that difficult, but "het kwartje moet even vallen". :)

++ 19/09/02 00:55 +0200 - Alex van den Bogaerdt:
>Then you're *not* doing the right thing.  You are saying that
>it is OK for updates to be 9 hours apart.  If you update
>at 00:00 and the next update is at 08:00, you will be saying
[...]

Ok. Your point is clear and taken. :)

I'll have to create new databases anyway, so now I can make it right as
well. I have now chosen for a heartbeat of 300 seconds. This is, I
guess, reasonable?

>Just "checkpoint" the database.  If there's no data available,
>say so by updating with either "U" for unknown or "0" for
>known-to-be-zero.

Ok. Got it. Will make some modifications to this script so it'll add
zero's if there are no articles posted, instead of leaving the database
alone.

In other words, with a heartbeat of 300 seconds, it'll set the entries
to "0" if there's a gap of less than 300 seconds and it'll set the
entries to "U" for gaps bigger than 300 seconds. Right? 

>> >>                         "RRA:AVERAGE:0.5:1:600",
>> >600 CPDs of 1 PDP per CDP  --> 600 minutes.
[...]
>In this case, there will be no difference between average, min and max.
>But if you're going to use 5 Primary Data Points into one Consolidated
>Data Point using Consosidation Function "x", it matters.

Oke. I'll try again. For the yearly graphs I have the following setup:

  RRA	:MAX		:0.99	:1440	:365
  RRA	:AVERAGE	:0.99	:1440	:365
  RRA	:MIN		:0.99	:1440	:365

This creates a database with 365 averages of 1440 values (one day). This
is right? This also creates a database with the same result, except that
the highest and lowest points of each of those 1440 values are used
instead of an average?

Those 365 averages are each the average number of articles posted per
minute and I'm able to change this to the average number of articles
posted per hour or day by multiplying it with 60 or 1440 with a CDEF
function at the time I create the graphs. Right?

The third column is used to tell RRDtool what to do if there are unkown
values (unknown PDPs). In my understanding, I could have RRDtool create
my CDPs, even if one or many PDP unknown.

>BUT: If you ask for "--end now --start end-3000minutes" and "now"
>happens to be "HH:MM" where "MM" is not exactly a multiple of 5
>(so: Not 10:55, 11:00, 11:05, 11:10 and so on) it may be possible
>that RRDtool selects another RRA as the best match.
[...]

What is the idea behind this?

>> Then function of this third field, I'm complete gone.
>I'm 100.7% sure I explained this *very* recently on this list or on
>the MRTG list.  Recent as in: This week.  Google for "50%" and my
>name or so.

I didn't find that post, but came across another one from the first half
of August this year. And I guess I have it understood by now: the third
column is used to tell RRDtool what to do if there are unkown values
(unknown PDPs). In my example above, I can have RRDtool create my CDPs,
even if one or many PDP unknown.

>> Thank you! I have probably some more days to go before the results are
>> the way I want them, bit this is looking promissing...
>
>Please do share an URL for us to view.  Maybe even accompanied by
>some scripts and INN config.  This will help others to do the job.

Sure. As soon as I'm a bit more finished with it. At this time it's
still less than some "extremely quick & extremely dirty" scripts. :)

Thanks again, it maybe takes some time, but in the end I'll
understand... :)

-- 
# Rejo Zenger
# rejo at sisterray.xs4all.nl, pgp: see headers, http://www.xs4all.nl/~sister

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