On 15.10.2012, at 16:16, Travis Griggs <[email protected]> wrote:
> A friend suggested I take a look at RRDTools for a problem I'm dealing with. > We're monitoring a number of custom devices in the agricultural world. We did > a naive "just store the telemetry in a database" thing originally. It was a > quick prototype that was contracted out. We quickly ran out of room. Even > telemetry at a trickle adds up fast. Since it was a Smalltalk database, I > built a custom edge triggered data collector that radically reduced the data, > since we mostly care about changes and when the occur. But that's not a long > term solution for us. So I'm looking at RRD. After a couple hours > reading/growsing/playing, I'm left with the following questions: > > 1) Each device we keep track of telemetry for, has a couple of different > measures. I've concluded that we shouldn't try to store dissimilar data types > in the same rrd file, even with separate RRAs. For example, we keep track of > battery voltage, and an hour's average is plenty high enough resolution for > us, but we also keep track of hydraulic pressures, and we'd really like to > have these at a minute resolution. It seems I'd be best served by having > different rrd's for these, one with a battery voltage DS, and the other with > pressure DS's. > yes separate rrds with different step sizes. > 2) While some of our data is scalar data (pressure, voltage, signal > strength), others is just binary status. Is it on or off? I'm not convinced > that binary status is easy to do with RRD, without playing some pretending > games. For most of the binary values, we tend to want to record any change in > them at a minutes resolution (that's how often the telemetry can come in). > But we don't ever want to "average them away" or anything. Changes are > usually infrequent (at most once per every couple of hours), but we want to > know exactly when they happened and not "lose" any of them, at least for a > given backwards time interval, such as a growing season (e.g. ~5 months). > Should I be looking at doing an alternative storage scheme for these, rrd's > for the scalar info, and something different for the edge triggered binaries? > if you need exact time (events) you should store them separately but if you wat to know the percentage the switch was off or on you clud setup a rather lowres rrd. if the changes are realy infrequent you could even calcilate when thy happene from the ratio hth tobi > Thanks for any help/direction/feedback/tips. > > -- > Travis Griggs > "A vital ingredient of success is not knowing that what you're attempting > can't be done." -Terry Pratchett > > _______________________________________________ > rrd-users mailing list > [email protected] > https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users > _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
