HP Integrity Virtual Machines Installation, Configuration, and Administration Version A.03.50

— SAS adapters supported by the SASD driver
— iSCSI adapters supported by the ISCSI driver
If the physical storage is not connected with one of above adapter and driver types, it cannot
be used by a virtual machine. Use the ioscan command to display the VM Host storage
that is connected to adapters and drivers.
• Any VM Host attachable devices available for use by a virtual machine must be supported
by the guest OS to which it is attached. If the physical device is not supported by the guest
OS, the device cannot be attached to the virtual machine.
7.2.1.2 Performance of Virtual Devices
To meet the performance requirements of applications running in guests, consider the potential
performance of each type of Integrity VM storage device.
Different types of virtual media have different effects on the performance of the virtual device
because they communicate differently with the VM Host to complete virtual machine I/O
operations. To understand the effect of the virtual device type on potential performance, consider
the Integrity VM storage I/O stack illustrated in Figure 7-1.
Figure 7-1 Integrity VM Storage IO Stack
HP-UX
Interface Driver
HP-UX
Interface Driver
HP-UX
Interface Driver
Physical Adapter Physical Adapter Physical Adapter
Physical Media Physical Media Physical Media
VM Host Driver Services
File Systems Layer
Virtual File Disk
Logical Volume Managers Layer
Virtual LvDisk
Disk Drivers Layer
Virtual Disk
Attached Devices
Integrity Vm Passthrough
Drivers Layer
For a virtual I/O operation to be completed, it has to travel round trip between the virtual storage
adapter and the VM Host physical storage device. The longer the path is, the longer it takes for
virtual I/O to be completed. As shown in Figure 7-1, a virtual I/O operation must traverse each
software layer in order, from where it originates to the physical media. For example, a virtual
I/O operation for a Virtual FileDisk must traverse any logical volume managers the file system
86 Creating Virtual Storage Devices