72% is my rule of thumb for write heavy production stuff (my absolute limit would be 75%) but it depends on record-size, raidz-level, if you have mostly write or mostly read workloads, how big your files are, how many snapshots you have, if you have a dedicated ZIL-Device and much more. For a Home-NAS (Movies etc) you can easy go up to 85%...if it's a "~WORM" workload maybe 90%...but resilvering can then be a thing of days (weeks?), depends on the raidz-level or mirror etc.

>Yeah, that's a myth now. It's not current advice.

It's not and you know it, keep it under 72% believe me if you want a performant zfs (especially if you delete files and have many snapshots...check the YT linked at the end)

>>Keep pool space under 80% utilization to maintain pool performance. Currently, pool performance can degrade when a pool is very full and file systems are updated frequently, such as on a busy mail server. Full pools might cause a performance penalty, but no other issues. If the primary workload is immutable files (write once, never remove), then you can keep a pool in the 95-96% utilization range. Keep in mind that even with mostly static content in the 95-96% range, write, read, and resilvering performance might suffer.

https://web.archive.org/web/20150905142644/http://www.solari...

And under no circumstances go over 90%:

https://openzfs.github.io/openzfs-docs/Performance%20and%20T...

>An introduction to the implementation of ZFS - Kirk McKusick

https://www.youtube.com/watch?v=TQe-nnJPNF8