3/26/2014
VirtualBox, Speeding up a guest VM
virtualbox is a virtual machine technology that runs on many host operating systems
virtualbox offers a number of "device types" for storage controller
IDE slowest
SATA fast
SCSI faster
SAS fastest
choosing the fastest supported by an guest operating system can substantially speed up the vm
rules of thumb:
IDE for XP
buslogic SCSI for old Linux
lsilogic SCSI for 2003 or Vista and 2008
lsi-sas for Windows 7 and later
[ always make sure the "Host I/O" option is "checked" ]
existing virtual disks can be moved from one controller type to another
[ avoiding the infamous STOP 0x7B ]
for windows a new controller should be added to the vm while it is shutdown
boot from the original controller, let pnp install a driver for the new controller
shutdown and move the boot volume and all other volumes to the new controller
use IDE for CD/DVD mounting and to control the favored boot device order
for linux if after adding a new controller type
the boot kernel complains it cannot find any volumes
Reading all physical volumes
No volume groups found
Volume group "VolGroup00" not found
(Unable to access resume device (/dev/VolGroup00/LogVol01)
mount could not find filesystem '/dev/root'
a new controller should be added to the vm while it is shutdown
boot from the original controller and use mkinitrd to build a new initrd
See how-to-migrate-rhel5-kvm-to-hyper-v for a mkinitrd demonstration