On Wed, Nov 20, 2002 at 09:12:57PM +0000, Jim Breton wrote: > What is the advantage of having multiple archives (with different sample > intervals) if you are only graphing one of these?
You're not, as Tobi explained. > For example, if I am graphing network i/o on a system and taking samples > every 5 minutes, why would I also want to create another RRA which takes > samples once per hour? An RRA doesn't take samples. An RRA stores normalized and consolidated data. It is ready to graph data. > I realize that would make a useful graph as well, > but I don't see how to "get it out" of the RRA when you graph it, since > it's under the same Data Source; so as far as I can tell the only way to > determine hourly results based on the above RRD would be to extrapolate > your 5-minute samples. But I'm sure I must be missing something! If you're going to generate an image where each pixel shows one hour of data, you don't want to to the math on 12 5-minute samples for each of your 400 pixels. It is much faster when you already have the data in a 1-hour resolution at hand. You don't *need* it, it is just nice to have. a) retrieve 12 samples, add them, divide by 12, display or b) retrieve 1 sample, display Another good reason is that you may want to choose not to store 2 years worth of data in a 5-minute resolution. Unless of course you want to actually display the data from way back in high resolution. a) 365+366 days * 288 samples per day = 210528 samples or b) 2.5 days * 288 samples and 365+366 days * 1 sample = 1451 samples HTH Alex -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://www.ee.ethz.ch/~slist/rrd-users WebAdmin http://www.ee.ethz.ch/~slist/lsg2.cgi
