HP vPars and Integrity Virtual Machines V6.1 Administrator Guide

• Overlapping physical storage allocated for different backing store types.
If a guest uses a logical volume (for example, rlvol1) as a backing store device, the disks
used by the volume group on which the logical volume is made (for example, /dev/vg01)
cannot be used as backing stores.
• Veritas VxVM DMP device files (files under /dev/vx/rdmp/) are not supported by Symantec
for whole disk backing stores for virtual machines.
You can use the ioscan and sam commands to detect these conflicts. If you force guests configured
with these conflicts to start, data corruption might occur.
On the VSP, do not extend a logical volume (LVM or VxVM) used as a backing store for a guest
root disk. If you do this, the guest panics on its next reboot with the following error:
System panic: all VFS_MOUNTROOTs failed: Need DRIVERS.
The guest should be able to boot if the logical volume is reverted (using lvreduce in case of LVM)
to its original size. If this fails, the guest root device has been corrupted, and the guest operating
system must be reinstalled.
An AVIO logical volume backing store not used as a root disk can be extended while the guest is
online. For HP-UX 11i v3 guests using AVIO, the guest is notified of the increased size of the
backing store for logical volumes as well as raw disks, and the guest can take the appropriate
actions to use the larger size.
For a SCSI logical volume used as a backing store for a guest data disk, you can extend the volume
after removing it from the guest using the hpvmmodify command. After extending the volume,
use the hpvmmodify command to add the volume to the guest. Do not modify a logical volume
used as a backing store without first removing it from the guest.
After you extend the logical volume, use operating system commands on the guest to extend its
file system.
NOTE: When you create a file system using the sam command on an HP-UX guest, do not
initialize the disk. This option returns an error and the file system is not created.
11.11.1 The vPars/VM device database file
The vParVM device management stores vPar/VM device mapping information in the device
database file (/var/opt/hpvm/common/hpvm_mgmtdb). This file is divided into three sections:
• The header, which states that the file cannot be hand edited.
• The restricted device section, which contains a list of host devices that guests are not allowed
to access.
• The guest devices section, which contains devices, both storage and network, that guests are
configured to use.
Do not edit the hpvm_mgmtdb file directly unless you are specifically advised to do so. Always
use supported Integrity VM commands (such as hpvmmodify or hpvmdevmgmt) to modify virtual
devices.
11.11.2 Using the hpvmdevmgmt command
To list and modify the devices used by the VSP and the vPars/VMs, use the hpvmdevmgmt
command.
Table 30 describes the options to the hpvmdevmgmt command.
190 Managing vPars/VMs