Best Practices for Integrity Virtual Machines

13/19
easiest to set up because they are typically already set up on the VM Host and they typically only
require insf to create a device file for them to be used as virtual storage for a VM
Logical volumes are fairly easy to manage with SMH and other tools. Administrators accustomed to
setting up separate logical volumes are already familiar with such tools. The logical volume should
be used in raw format – creating a file system there is a waste of time. A single physical disk may be
more efficiently used by dividing it into multiple logical volumes, but this comes at a manageability
price in the event that disk should fail.
File and file system management is familiar to all system users, making files the most convenient of all
the virtual storage options. Integrity VM provides functionality with the hpvmdevmgmt command to
create files for use as virtual storage. Clearly, naming of directories, files, etc is useful and important
in understanding and organizing what VM is using which file for storage. While file system
commands are easy to use, a single typographical error can destroy a lot of data. Remember to
create the file systems such that they are capable of containing large files (larger than 2 GB).
Partitions are the least manageable simply because there are few tools on HP-UX to manage them.
The idisk utility is difficult to use and its documentation misleads the user into believing that the
partition type may be important for use as virtual storage. Any type will suffice, but one is forced to
create an EFI partition first. This is the only one you will need for virtual storage, so make it
sufficiently large for your planned utilization.
Stripe Disks On the Host Where Possible
Creating volume groups on multiple disks should be done on the VM Host wherever possible. This is
especially true when the volume group is configured with striping across those disks. Striping across
multiple disks on the VM Host delivers significantly better performance than virtualizing each of those
disks and striping across them on the VM. This also minimizes the number of devices required on the
VM.
Summary
Generally speaking, there are two rules of thumb when consolidating with VMs and configuring
virtual devices for those VMs – keep it simple and, when in doubt do it on the VM Host.
Wherever possible, keep configurations simple. As mentioned earlier, if large mass storage is
required then use whole physical disks for virtual disks – don’t bother using logical volumes or files for
them. The more complex the configuration, the more likely it is to become problematic
Virtual DVD
Virtual DVDs may be mapped to files or physical DVD drives (logical volumes cannot be used for
virtual DVD).
Performance
One clear advantage of files over the use of physical DVDs is performance – file I/O will be faster
than from a physical DVD. Moreover, such files may be designated as shared (using hpvmdevmgmt),
allowing these virtual DVDs to be used by multiple virtual DVD drives in multiple VMs –
simultaneously. Physical DVDs should not be used simultaneously by VMs and, hence, should not be
designated as shared.
Ease of Use
Reflecting on the previous section, Virtual Mass Storage, it follows that files are easier to manage than
physical DVDs. Once the media is available as a file, for example, as an ISO image, it need not be
present in the physical DVD drive to be used by a virtual DVD. It is often a good practice to define
the virtual DVD with bus/device/target of 0/0/0 to accommodate assumptions of where DVD is
located (e.g., installing ISV software). This can be achieved by creating your VM such that its first
resource (amongst disk, DVD, or network) is the virtual DVD drive and/or creating the virtual DVD