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Manual Pages  — ZFSBOOTCFG


zfsbootcfg – specify zfsboot options for the next boot



zfsbootcfg <options >


zfsbootcfg is used to set boot.config(5)-style options to be used by zfsboot(8) or gptzfsboot(8) the next time the machine is booted. Once zfsboot(8) or gptzfsboot(8) reads the information, it is deleted. If booting fails, the machine automatically reverts to the previous boot configuration. The information is stored in a special reserved area of a ZFS pool. zfsboot(8) or gptzfsboot(8) read the boot option information from the first disk found in the first ZFS pool found.


  The kenv(1) variable that identifies a pool for which the options are written.
  The kenv(1) variable that identifies a disk within the pool where the options are written.


Try to boot to a new boot environment without changing the bootfs property of a pool:

    zfsbootcfg zfs:tank/ROOT/newbe:"

To clear the boot options:

    zfsbootcfg "


boot.config(5), gptzfsboot(8), zfsboot(8)


zfsbootcfg appeared in FreeBSD 11.1 .


This manual page was written by Andriy Gapon <Mt avg@FreeBSD.org>.


At the moment, zfsbootcfg uses the vfs.zfs.boot.primary_pool and vfs.zfs.boot.primary_vdev kenv(1) variables to determine a ZFS pool and a disk in it where the options are to be stored. The variables are set by the ZFS boot chain, so there is an assumption that the same boot disk is going to be used for the next reboot. There is no zfsbootcfg option to specify a different pool or a different disk.

zfsbootcfg should be extended to install new zfsboot(8) blocks in a ZFS pool.

ZFSBOOTCFG (8) May 24, 2017

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