Store machine status on Graphite time-series to later extract KPIs

Question

having a machine which sends (not regularly) its status values 0, 1, 2, we're storing it in Graphite. Now the status means:

• 0 - stopped
• 1 - working
• 2 - stopped by anomaly

The requested KPIs to extract are the classical ones: how much time on status 0 or 1 or 2 in a day or a week? Before reinventing the wheel, we're looking at the best way to compute those PKIs and if in Graphite (or possible other time-series solution) there are already function which deal with summing the time where the data point value is just a condition. Clearly the time intervals to sum are not stored, it's the time elapsed between a data point and the next one.

Or should the data pre-processed to compute the time intervals and then store three data sets like: status.working, status.stopped, status.alarm and for each store when the specific "event" started and how much it lasted?

There are other KPIs, for example the number of alarms in a day. Receiving two status data points in a row both indicating status "2" is actually a single alarm condition and must count as 1.

So, is there a best way to store such data without pre-processing it? It sounds to be a common pattern but (shame on us?) we have not found this topic well explored.

Thanks.

Answer 1

Graphite has a number of functions that could help you here. One that stands out is the summarize() function in which you can pass an aggregation method (in this case sum) and a duration in minutes/hours/days/weeks/etc), take a look here

isNonNull is another useful function: it can be used to determine the existence of a datapoint regardless of the value.

When you say that the machie reports a value 0 to indicate it has stopped - does it actually send that value or does it report nothing? This is an important detail and will have some bearing on the end result of your solution.