Disk Space Alert

[Tractorboy]

I do not like to alert on physical free space or free percentage as this does not account for that disks current usage.

Consider the scenerio of many many servers, each running against a templated set of disk items. Each server has a different initial size, and different disk consumption rates. How would you define a standard alert? 10000 bytes may get used in an hour, 15% may give years of free space.

I have a solution in place that I'd like to transistion, this alerts on x days of available space.

Any thoughts on how to build something that would make available this information? I am thinking it a little too complex for a calculated process?

Anyone up for the challenge?

[nleaman]

I think almost everyone would find it very useful to be able to monitor and report on projected time to hit a specified threshold (x days of available space). The problem (for me) is the projection part, specifically the math. Determining a single projected date is tricky. I have done some work like this a few months ago and used rrdtool's LSLSLOPE function. LSLSLope is one of the formulas that can provide a trend line and rrdtool provides it in a way that was easiest for me to use.

Basically, I plotted many LSLSLOPE lines, each starting from a different point of time in the past. Each would provide a projected date. I would get a single final projected date by taking the average of them all (weighted towards the more recent trend lines). The amount of history for any given volume is a big factor in determining a realistic date.

It would be worth it at some point in future for me to integrate this into Zabbix. It's a matter of exporting historical disk utilization data, creating an RRD with that data, getting the projected data (as described), send that date to a Zabbix Trapper item.

Kludgy indeed, but I know this would work. I would probably just do it every 12 or 24 hours per volume as well.

I attached RRD graphs that show a bit of how it's calculated. Notice in the lower right corner there is a final projected date (also represented by the vertical red line). The grey vertical line is just the current day that the graph was run on.