[rrd-users] newbie rrd question - probably a very old issue

Alex van den Bogaerdt alex at ergens.op.het.net
Fri Aug 31 19:35:57 CEST 2007

On Fri, Aug 31, 2007 at 01:07:44PM -0400, Dan Gahlinger wrote:

> for example, we do a 1 day graph and the "maximum" is 90
> we do the same graph for 1 week and the "maximum" has magically changed to 
> 30
> do it again for 1 month, and it gets even worse.

An RRA stores average, minimum or maximum rates.
GPRINT writes the average, minimum or maximum on the graph.

If you are graphing data from an AVERAGE RRA, you can print the
maximum of those averages, not the maximum out of another RRA.

1 step per row:  1,2,3,4,5,6,7,8,9,10,11,12

MAX(1,2,3,4,5,6,7,8,9,10,11,12) -> 12

consolidation function average, 3 steps per entry:

avg(1,2,3),avg(4,5,6),avg(7,8,9),avg(10,11,12) -> 2,5,8,11
MAX(2,5,8,11) -> 11, not 12.

consolidation function average, 6 steps per entry:
avg(1,2,3,4,5,6),avg(7,8,9,10,11,12) -> 3.5 , 9.5
MAX(3.5,9.5) -> 9.5, not 12

and so on.

> but when we check the raw data, we can see all the data points are there.
> if we have so many data points, it shouldn't be consolidating the data, but 
> it is.

It shouldn't? Or perhaps you ask it to do so but don't want to?

> and it's driving me crazy trying to figure out why.
> we thought of using separate data files for min, max and average, but triple 
> the data storatge and triple the overhead is killing our server.
> can someone tell us what we're doing wrong or give us a suggestion so that 
> the data will be reported properly?

Post the command you use to create your RRD file.  Also post the
relevant parts of your graph command.

Keep it simple. We don't need to see all fancy formatting and such,
a simplified example would be best, as long as it shows what you are
talking about.

Alex van den Bogaerdt

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