VERITAS Volume Manager 4.1 Administrator's Guide

Chapter 2 76
Placing Disks Under VxVM Control
When you add a disk to a system that is running VxVM, you need to put the disk under VxVM
control so that VxVM can control the space allocation on the disk. Unless you specify a disk
group, VxVM places new disks in a default disk group according to the rules given in “Rules
for Determining the Default Disk Group” on page 137.
The method by which you place a disk under VxVM control depends on the circumstances:
• If the disk is new, it must be initialized and placed under VxVM control. You can use the
menu-based vxdiskadm utility to do this.
CAUTION Initialization destroys existing data on disks.
• If the disk is not needed immediately, it can be initialized (but not added to a disk group)
and reserved for future use. To do this, enter none when asked to name a disk group. Do
not confuse this type of “spare disk” with a hot-relocation spare disk.
• If the disk was previously initialized for future use by VxVM, it can be reinitialized and
placed under VxVM control.
• If the disk was previously used for a file system,VxVM prompts you to confirm that you
really want to destroy the file system.
• If the disk was previously in use by the LVM subsystem, you can preserve existing data
while still letting VxVM take control of the disk. This is accomplished using conversion.
With conversion, the virtual layout of the data is fully converted to VxVM control (refer
the VERITAS Volume Manager Migration Guide).
• If the disk was previously in use by the LVM subsystem, but you do not want to preserve
the data on it, use the LVM command, pvremove, before attempting to initialize the disk
for VxVM.
• Multiple disks on one or more controllers can be placed under VxVM control
simultaneously. Depending on the circumstances, all of the disks may not be processed the
same way.
• When initializing multiple disks at once, it is possible to exclude certain disks or
controllers.
To exclude disks, list the names of the disks to be excluded in the file
/etc/vx/disks.exclude before the initialization. The following is an example of the
contents of a disks.exclude file:
c0t1d0
You can exclude all disks on specific controllers from initialization by listing those
controllers in the file /etc/vx/cntrls.exclude. The following is an example of an entry
in a cntrls.exclude file: