So I posted not too long ago that I had a drive failure in my RaidZ pool. Ordered a replacement disk (WD RED, purpose built for NAS), and tried resilvering only to see this after a short while...
https://github.com/openzfs/zfs/issues/10214 https://www.truenas.com/docs/hardware/notices/componentarticles/wdsmr/ https://blog.westerndigital.com/wd-red-nas-drives/
Turns out WD started pushing out a new disk technology called SMR, that's slower, and fails when rebuilding RAIDs due to heavy write operations, and specifically marketed it towards NAS users? WTF Western Digital?!
Anyway, disk RMAd, and a replacement CMR disk is on the way. I'll never buy WD drives again... Lesson learned the hard way.
Red plus drives should all be CMR as well