Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

102 Administering disks
Rootability
Booting root volumes
Note: At boot time, the system firmware provides you with a short time period during
which you can manually override the automatic boot process and select an alternate boot
device. For information on how to boot your system from a device other than the primary
or alternate boot devices, and how to change the primary and alternate boot devices, see
the HP-UX documentation and the boot(1M), pdc(1M) and isl(1M) manual pages.
Before the kernel mounts the root file system, it determines if the boot disk is a rootable
VxVM disk. If it is such a disk, the kernel passes control to its VxVM rootability code.
This code extracts the starting block number and length of the root and swap volumes
from the LIF LABEL record, builds temporary volume and disk configuration objects for
these volumes, and then loads this configuration into the VxVM kernel driver. At this
point, I/O can take place for these temporary root and swap volumes by referencing the
device number set up by the rootability code.
When the kernel has passed control to the initial user procedure, the VxVM configuration
daemon (
vxconfigd) is started. vxconfigd reads the configuration of the volumes in the
bootdg disk group and loads them into the kernel. The temporary root and swap
volumes are then discarded. Further I/O for these volumes is performed using the VxVM
configuration objects that were loaded into the kernel.
Setting up a VxVM root disk and mirror
Note: These procedures should be carried out at init level 1.
To set up a VxVM root disk and a bootable mirror of this disk, use the
vxcp_lvmroot
utility. This command initializes a specified physical disk as a VxVM root disk named
rootdisk## (where ## is the first number starting at 01 that creates a unique disk
name), copies the contents of the volumes on the LVM root disk to the new VxVM root
disk, optionally creates a mirror of the VxVM root disk on another specified physical disk,
and make the VxVM root disk and its mirror (if any) bootable by HP-UX.
The following example shows how to set up a VxVM root disk on the physical disk
c0t4d0:
# /etc/vx/bin/vxcp_lvmroot -b c0t4d0
Note: The -b option to vxcp_lvmroot uses the setboot command to define c0t4d0 as
the primary boot device. If this option is not specified, the primary boot device is not
changed.
If the destination VxVM root disk is not big enough to accommodate the contents of the
LVM root disk, you can use the
-R option to specify a percentage by which to reduce the