[rrd-users] Re: retroactively graphing data from logfile (newbie)

[Ryan Tracey]

On 5/25/05, Alex van den Bogaerdt <alex at ergens.op.het.net> wrote:
> On Wed, May 25, 2005 at 10:47:49AM +0200, Ryan Tracey wrote:
> 
> > > > RRA:AVERAGE:0.5:1:24
> > >
> > > One "step" per row, 24 rows.  That's not huge, is it?  You have
> > > asked for a database storing exactly one day (24 rows, one hour each).
> >
> > Hmm, I thought I was creating the facility to create daily averages.
> > But I should rather do something like "RRA:AVERAGE:0.5:1:x" where x is
> > the number of hours in the amount of days I want to store. Say, 144
> > for 6 days.
> 
> Yes.
>
> > Also, how would you best describe what the 0.5 does.  The beginners
> > guide seems to have glossed over that one.
> 
> Because that's in the documentation and I cannot make it much
> clearer for you.
> 
> Your RRA has "1" steps per row.  In your case, xff isn't used.
> You either do have unknown data, or you don't.

Thank you.  I should have RTFM. 
 
> > > I guess you mean "1115110805" is variable __AND__ it is a whole
> > > multiple of 3600 ?
> >
> > 1115110805 is variable, the timestamp in the first column, but not (I
> > suspect) necessarily a multiple of 3600.  Should it be?
> 
> How do you go from "2005-05-03-12" to anything not a multiple of 3600?
> 1115110805 means 2005-05-03T09:00:05   Where did those 5 seconds come
> from if you only input whole hours?

Arghh. I think I need more sleep.   

> If you indeed do only use whole hours, where did your example line
> come from?  Did you make it up?  Why?

I was indeed messing around with thetimestamp before I entered it.   
I added 5 seconds to each one.   When I first started entering data I
got an error because my first entry was exactly the same as the
"--start" time (or I interpreted the error mean that).  Taking a
short-cut, I simply added 5 seconds to each timestamp -- they'd still
be 3600 seconds apart.  I should rather have re-created the rrd.

> > > You want to update every 3600 seconds, or sooner.  If one timestamp
> > > is exactly on the hour, and the next timestamp is 5 seconds late,
> > > you'll loose an update.
> >
> > I'll change the step size to 1.5 hours  (5400).
> 
> That's not what I'm suggesting.  Especially not when your heartbeat
> stays 3600.  The heartbeat value monitors your input.

Sorry, I did mean heartbeat and not step size (back to the sleep thing again).  

> Last hour: 1117011600
> Next hour: 1117015200
> Difference 3600   <--- this is what heartbeat looks at
> Last update: 1117011600
> Next update: 1117015205
> Difference 3605   <--- heartbeat declares the input dead

Understood.

> If you update at:
> 
> 09:00   rate (GAUGE)  10
> 10:00   rate 20
> 11:00   rate 30
> 12:00   rate 40
> 
> then there's no problem.  Now, one of the updates fails:

Thanks very much for the examples.   They have helped!
 
> Next is to transfer these PDPs to the RRAs.
> 
> RRA:AVERAGE:0.5:1:24   "I need one PDP per row, I have 24 rows"
> RRA:AVERAGE:0.5:24:1   "I need 24 PDPs per row, I have 1 row"
> 
> Both RRAs cover the same amount of time.  However, the last one
> is more suitable for looking at large amounts of time (for instance,
> the yearly graph).

Thanks again for the explanations, examples and help.  I appreciate it.

Regards,
Ryan

-- 
Ryan Tracey
Citizen: The World

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