[Orca-users] Data accuracy

Blair Zajac blair at orcaware.com
Tue Apr 8 11:52:19 PDT 2003

> Santana Fernando wrote:
> Hi all, my question is related to the different plots available
> for a measurement and their accuracy.  It seems to me that if I
> get a high peak in CPU for example in a hourly graph, I can check
> it tomorrow by viewing a daily graph but the peak value seems to
> be lower than the actual peak value as seen a day before.
> Can someone explain why I don't see the same peak values in graphs
> that span a bigger time frame? Can the data peaks and spikes be
> maintained across all the graphs, that is hourly, daily, monthly,
> quarterly and yearly?

The longer time span plots consolidate data across a longer time span.
Orca uses the AVERAGE consolidation function, but there are also
MIN and MAX consolidation functions available.

In lib/Orca/Config.pm says what Orca does:

# The first RRA is every 5 minutes for 200 hours, the second is every
# 30 minutes for 31 days, the third is every 2 hours for 100 days, and
# the last is every day for 3 years.

Here RRA is Round Robin Archive.  The hourly and daily plots use the
5 minute average, weekly plots use the 30 minute average, monthly
plots use the 2 hour average, and quarterly and yearly plots use the
daily average.

If you want to change this, edit lib/Orca/Config.pm, delete all your
RRD files and rerun Orca.

If you want to use a different consolidation function, change all
occurrences of AVERAGE and average in lib/Orca/RRDFile.pm and
lib/Orca/ImageFile.pm to MAX and max.

I would gladly take patches to this to put this stuff into the Orca
config file.


Blair Zajac <blair at orcaware.com>
Plots of your system's performance - http://www.orcaware.com/orca/

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