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30 .Nd disk bootcode for BIOS-based computers
33 is used on BIOS-based computers to boot from a filesystem on disk device.
34 Depending on disk partitioning and boot file system, the
37 .Cm zfs pool boot area
40 partition of a disk with
42 .Ss IMPLEMENTATION NOTES
43 The GPT standard allows a variable number of partitions, but
45 only boots from tables with 128 partitions or less.
48 tries to find all ZFS pools that are composed of BIOS-visible
49 hard disks or partitions on them.
51 looks for ZFS device labels on all visible disks and in discovered
52 supported partitions for all supported partition scheme types.
53 Disks are probed in BIOS defined order.
54 After a disk is probed and
56 determines that the whole disk is not a ZFS pool member, the
57 individual partitions are probed in their partition table order.
58 Currently GPT and MBR partition schemes are supported.
60 The default boot partition is recorded into
64 and the default boot file system is determined at run time.
66 does support booting from the
73 The filesystem specified by the
75 property of the ZFS pool is used as a default boot filesystem.
78 property is not set, then the root filesystem of the pool is used as
81 is loaded from the boot filesystem.
84 is present in the boot filesystem, boot options are read from it.
86 The ZFS GUIDs of the boot pool and boot file system are made available to
91 will boot in fully automatic mode.
92 However, it is possible to interrupt the automatic boot process and
97 The filesystem specification and the path to
102 .Oo zfs:pool/filesystem: Oc Oo /path/to/loader Oc
105 Both the filesystem and the path can be specified.
106 If only a path is specified, then the default filesystem is used.
107 If only a pool and filesystem are specified, then
113 does support two commands to get information about the system.
115 can be used to list the content of named directory and
117 command can be used to query information about discovered devices.
118 The output format for ZFS pools is similar to that of
120 .Pq see Xr zpool 1M .
122 The configured or automatically determined ZFS boot filesystem is
126 variable, and also set as the initial value of the
130 .Bl -tag -width /boot/gptzfsboot -compact
132 parameters for the boot block
134 .It Pa /boot/gptzfsboot
139 is installed in combination with a
150 .Bd -literal -offset indent
151 installboot /boot/pmbr /boot/gptzfsboot /dev/rdsk/c0t0d0s0