Handling an out of space condition should be part of your test suite - it certainly was back when I looked after a Map reduce based Billing system at BT and that was back in the day when a cluster of 17 systems was a really big thing.
We actually did have monitoring on the capacity of the disk in question. We discovered during the analysis that it had been alerting the responsible team all day. They had just been ignoring it.
I was concerned that it's possible to read your comment as if it was critical of the parent - was that your intention?
Though for the system I mentioned one of the reasons they employed me as a developer was that I was also a sysad on PR1MES - an early example of devops maybe.