Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

Root disk mirrors

All the volumes on a VxVM root disk may be mirrored. The simplest way to achieve

this is to mirror the VxVM root disk onto an identically sized or larger physical

disk. If a mirror of the root disk must also be bootable, the restrictions for the

encapsulated root disk also apply to the mirror disk.

See “Booting root volumes” on page 114.

Warning: If you mirror only selected volumes on the root disk and use spanning

or striping to enhance performance, these mirrors are not bootable.

See “Setting up a VxVM root disk and mirror” on page 115.

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.

See the boot(1M) manual page.

See the pdc(1M) manual page.

See the isl(1M) manual page.

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

Administering disks

Rootability

114