[dotancohen]

That's far more complicated and fragile. Where are you storing this log of disk usage? If you already have some external time series database then this is already a solved problem. But for a single server, desktop, or embedded device you'll need a database or text log, a cron job to measure it, and another script to parse, make predictions, and then raise alerts.

And a single large dump to disk, like some daemon suddenly bugging out and writing incessantly to logs, will render all that moot anyway.