With OpenZFS 2.2.0-rc3 out in the wild, it won’t be long until the official release lands.
If your distro is quick to update packages and you use the binary ZFSBootMenu EFI to boot your system - DO NOT run zpool upgrade! OpenZFS 2.2.0 includes a number of new feature flags, two of which are problematic for older versions of ZFS:
zfsbootmenu / > dmesg | grep "v2.1.12"
[ 1.147795] ZFS: Loaded module v2.1.12-1, ZFS pool version 5000, ZFS filesystem version 5
zfsbootmenu / > zpool import ztest
This pool uses the following feature(s) not supported by this system:
com.delphix:head_errlog (Support for per-dataset on-disk error logs.)
org.openzfs:zilsaxattr (Support for xattr=sa extended attribute logging in ZIL.)
cannot import 'ztest': unsupported version or feature
zfsbootmenu / > zpool import -o readonly=on ztest
This pool uses the following feature(s) not supported by this system:
com.delphix:head_errlog (Support for per-dataset on-disk error logs.)
cannot import 'ztest': unsupported version or feature
com.delphix:head_errlog breaks both read-only and read-write imports, org.openzfs:zilsaxattr breaks read-write imports.
As soon as OpenZFS 2.2.0 is tagged, we’ll cut a new build of ZFSBootMenu with updated ZFS userland/kernel modules. Until that happens, make sure you do not run zpool upgrade, as you’ll have an unbootable system. If you’re here because that has happened, wait until a new release of ZFSBootMenu is tagged and published and then follow the directions at Portable ZFSBootMenu to recover your system.