On Thu, Mar 22, 2001 at 09:50:14AM -0500, Dan McGinn-Combs wrote: > > I think this is pretty much what I'm looking for, Paul. I was trying to come > up with an example for Clifton. > > Your example is right on the money, but let's move it over to hard disk > space. I have a user drive which began life as 0% utilized. Each week it got > 5% more utilized, i.e. 0% - 5% - 10% - 15% - 20%. I can pretty much predict > with some certainty that after 20 weeks it will be completely full. I can > give that information to management and offer them a choice, either you ask > individuals to clean up the data they put on the drive, or you buy a new > drive in 15 more weeks. > > The trend line allows me to make that case.
OK, I got it now. Yes, this is really important for any kind of professional. One problem with doing this with RRDgraph is that it's not really designed to graph things out into the future, only to graph what's already observed. (Though you might be able to coax it to do that, I don't know.) For this kind of thing, I don't try to get it directly out of RRD or a similar logging/graphing tool. Instead what I will usually do is try to get the most relevant data out of the collection tool into some Ascii format and import it into <shudder> MS Excel. Once it's in there, with the builtin functions, it's easy to do other graphing, linear or curve fitting, etc. Not to mention that if you put that Excel graph into a Powerpoint slide, put a bold-faced heading on it, and print it in color, then it *must* be true! ;-) One advantage about doing it this way is that you can fit the data to additional factors which may not be available by doing it directly in RRD which deals mainly with time series data. Suppose, in your example, that you think the source of the rapid growth of data on the hard disk is due to all the staff that's been added to that department in the last 4 weeks. You can put that in as your "X" variable, and curve fit to that, then you can tell the management with even more accuracy, "We need a new drive before that department gets to 28 people, which looks like it would happen 15 weeks from now at the present rate." -- Clifton -- Clifton Royston -- LavaNet Systems Architect -- [EMAIL PROTECTED] WWJD? "JWRTFM!" - Scott Dorsey (kludge) "JWG" - Eddie Aikau -- 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
