Creating An Alternate Boot Disk - HP -UX 11i Administrator's Manual

Detaching a link does not disable sparing. That is, if all links to a physical volume are detached
and a suitable spare physical volume is available in the volume group, LVM uses it to reconstruct
the detached disk. For more information on sparing, see
Disk Sparing" (page
You can view the LVM status of all links to a physical volume using vgdisplay with the -v option.
Restoring a detached link to a physical volume, or reattaching it, makes that link available to the
volume group. LVM can begin using that link as necessary to access the disk.
To reattach a specific path to a physical volume, use the pvchange command with the -a option.
For example, enter the following command:
# pvchange -a y /dev/dsk/c5t0d0
Because detaching a link to a physical volume is temporary, all detached links in a volume group
are reattached when the volume group is activated, either at boot time or with an explicit vgchange
command, such as the following:
# vgchange -a y /dev/vg02

Creating an Alternate Boot Disk

NOTE: Version 2.0 and 2.1 volume groups do not support bootable physical volumes. You
cannot create an alternate boot disk in a Version 2.0 or 2.1 volume group.
With non-LVM disks, a single root disk contains all the attributes needed for boot, system files,
primary swap, and dump. Using LVM, a single root disk is replaced by a pool of disks, a root
volume group, which contains all of the same elements but allowing a root logical volume, a boot
logical volume, a swap logical volume, and one or more dump logical volumes. Each of these
logical volumes must be contiguous, that is, contained on a single disk, and they must have bad
block relocation disabled. (Other noncontiguous logical volumes can be used for user data.) For
more information on the swap and dump devices and their configuration, see HP-UX System
Administrator's Guide: Configuration Management.
The root logical volume contains the operating system software and the root file system (/).. The
boot logical volume contains the boot file system (/stand). You can combine the root and boot
logical volumes into a single logical volume or keep them separate. Whether you use a single
combined root-boot logical volume, or separate root and boot logical volumes, the logical volume
used to boot the system must be the first logical volume on its physical volume. It must begin at
physical extent 0000 to boot the system in maintenance mode.
If you newly install your HP-UX system and choose the LVM configuration, a root volume group is
automatically configured (/dev/vg00), as are separate root (/dev/vg00/lvol3) and boot
(/dev/vg00/lvol1) logical volumes. If you currently have a combined root and boot logical
volume and you want to reconfigure to separate them after creating the boot logical volume, use
the lvlnboot command with the -b option to define the boot logical volume to the system, taking
effect the next time the system is booted.
The swap logical volume is the system's primary swap area and is typically used for dump. The
swap logical volume is often on the same physical disk as the root logical volume. However, you
can configure it (and the dump logical volumes) on a different physical disk than the root logical
volume.
If you create your root volume group with multiple disks, use the lvextend command to place
the boot, root, and primary swap logical volumes on the boot disk.
TIP: You can use pvmove to move the data from an existing logical volume to another disk if
necessary to make room for the root logical volume. For more information, see
a Different Physical Volume" (page
To create a new root volume group with an alternate boot disk, follow these steps:
88 Administering LVM
27).
73).
"Increasing Disk Redundancy Through
"Moving Data to