[rrd-users] rrd_hwreapply problem

[Livio Zanol Puppim]

Hi!

I'm trying to reapply Holt-Winters forecasting to my company RRDs but
I'm having a little problem.
I'm using rrd_hwreapply perl script from Stanislav Sinyagin and
RRDTool version 1.2.15 on a debian stable.

My RRDs files are based upon MRTG config files. They have two DSs (ds0
and ds1) representing in and out traffics, have a step of 300 seconds
(5 minutes) and have the following RRAs:
1     pdp_per_row (storing ~30 days of data) - 5 minutes avarage
6     pdp_per_row (storing ~15 days of data) - 30 minutes avarage
24   pdp_per_row (storing ~2 months of data) - 2 hours avarage
288 pdp_per_row  (storing ~2 years of data) - 1 day avarage

When I use rrd_hwreapply to apply the forecasting, all the data in the
last three RRAs before what the 1 pdp_per_row has stored are lost.
- So let's say that my last data at the 1 pdp_per_row is at
06/20/2008. Then, on my last RRA (288 pdp_per_row) I only have 1 month
of historical data, and all historical data at this RRA is lost...

This is explained by the fact that the script creates a new RRD and
simple call the "rrdtool update" passing the DSs calculed with the 1
pdp_per_row entry. But I want the script to keep the old data as well
(2 years of work lost!!). Unfortunely, as I've seen, It's not possible
with this script.

Anyone knows a way to do this?

Thank you
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[]'s

Lívio Zanol Puppim