HP Integrity Virtual Machines 4.3: Installation, Configuration, Administration

6.2.2.3.1 Virtual Disks
A Virtual Disk is an emulated SCSI disk whose virtual media comes from a VM Host disk LUN.
The VM Host disk LUN is specified using a character device file. The character device file is
owned by the HP-UX esdisk or sdisk driver.
Virtual Disk resources cannot be shared simultaneously across active virtual machines (except
in certain cluster configurations, as indicated in this manual). Only one active virtual machine
at time can be given a particular Virtual Disk resource. Virtual Disk resources can be changed
dynamically among active virtual machines.
To prevent virtual media conflicts that can result in data corruption, a proper accounting of how
the VM Host whole disks are allocated for use by Virtual Disks needs to be done, as described
in Section 6.2.1.4 (page 99).
The agile Virtual Disk resource statement takes the form:
disk:scsi::disk:/dev/rdisk/diskX
where /dev/rdsk/diskX is an HP-UX esdisk character device file.
The legacy Virtual Disk resource statement takes the form:
disk:scsi::disk:/dev/rdsk/cXtYdZ
where /dev/rdsk/cXtYdZ is an HP-UX sdisk character device file. Use of agile device names
for configuring storage devices is highly recommended as it provides multipathing benefits.
These device files can be located for a VM Host LUN using the ioscan command. These system
files are installed and removed using the insf and rmsf commands, respectively. Device files
are created automatically by the VM Host for any storage it identifies during boot. New devices
connected or created after boot time, require the use of ioscan and insf to create the new
sdisk device files. To remove old device files for storage that is no longer present, use the rmsf
command. For example:
# ioscan
# ioscan -NfunC disk
disk 64000/0xfa00/0x10 esdisk CLAIMED DEVICE
HP HSV210
/dev/disk/disk /dev/rdsk/disk
6.2.2.3.2 Virtual LvDisks
A Virtual LvDisk is an emulated SCSI disk whose virtual media is provided by a raw VM Host
logical volume. To specify a VM Host logical volume, use a character device file. The character
device file is owned by either LVM or VxVM.
Virtual LvDisks cannot be shared simultaneously across active virtual machines. Only one active
virtual machine at time can be given a particular Virtual LvDisk resource. Virtual LvDisk resources
can be changed dynamically between active virtual machines (see Section 6.3 (page 113)).
Logical volumes can be created using the sam utility or the Veritas Enterprise Administrator.
Alternatively, logical volumes can be created using the commands available with the volume
manager. All logical volumes are created on whole disks. The sizes of the logical volumes come
from the space available from their respective volume group types; that logical volume size can
be increased without loss of data in the volume. The character devices for the logical volumes
are created by their respective volume managers at the time the logical volume is created. Also
to avoid file system corruptions for the VM Host and guest , use only raw logical volumes that
contain no VM Host file systems and are not currently mounted on the VM Host.
To prevent data corruptions, keep an account of logical volumes for Virtual LvDisks. To help
with the accounting, use all logical volumes within a given volume group for a single virtual
machine. When logical volumes are configured this way, you only have to keep track of the
104 Creating Virtual Storage Devices