Bug 257080

Summary:	[hyper-v] FreeBSD 13.0 can't boot on hyper-v 2012 with root on zfs
Product:	Base System	Reporter:	Dmitry <4diman>
Component:	bin	Assignee:	freebsd-virtualization (Nobody) <virtualization>
Status:	New ---
Severity:	Affects Many People	CC:	grahamperrin, whu
Priority:	---
Version:	13.0-RELEASE
Hardware:	amd64
OS:	Any

Description Dmitry 2021-07-09 13:52:44 UTC

It show menu, then tying to load kernel, but fails.
ZFS: i/o error - all block copies unavailable

Installed via default installer.
Same setup on hyper-v 2012r2 works fine.
Same setup on FreeBSD 12,11,10 on hyper-v 2012 works fine.
Setup with root on UFS works fine.

A few more info, including one workaround:
https://forums.freebsd.org/threads/freebsd-13-0-with-root-on-zfs-on-hyper-v-2012.81168/