HP-UX vPars and Integrity VM V6.3 Administrator Guide

in guest A. The other path must not be used as a backing store by guest A or by any other
guest or the VSP.
• 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.
You can use the ioscan command to detect these conflicts. If you force guests configured with
these conflicts to start, the data might get corrupted.
Do not use Veritas VxVM DMP device files (files under /dev/vx/rdmp) used as a backing store
for a guest root disk, on the VSP. If this is done, then explicitly run insf -e so that partitions on
DMP node gets reflected on the physical disk as well. If you do not run insf -e there is no way
for VxVM to communicate the partition information on the DMP nodes to HPUX I/O tree.
NOTE: If DMP naming scheme changes, then you have to update guest configuration file using
the hpvmmodify command.
SCSI information will be displayed only for DMP devices presented through NPIV.
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 must 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 is 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 and raw disks, and the guest can take appropriate actions to
use the larger size.
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. It returns an error and the file system is not created.
13.19.1 VM or vPars device database file
The vPar or VM guest device management stores vPar or VM guest 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.
13.19.2 Using the hpvmdevmgmt command
To view and modify the devices used by the VSP and the vPar or VM guests, use the hpvmdevmgmt
command.
13.19 Managing the device database 249