Windows 2008 boot process

1.System is powered on 2.The CMOS loads the BIOS and then runs POST 3.Looks for the MBR on the bootable device 4.Through the MBR the boot sector is located and the BOOTMGR is loaded 5.BOOTMGR looks for active partition 6.BOOTMGR reads the BCD file from the \boot directory on the active partition 7.The BCD (boot configuration database) contains various configuration parameters( this information was previously stored in the boot.ini).bcdedit /export save-bcd GUIDs program objects 8.BOOTMGR transfer control to the Windows Loader (winload.exe) or winresume.exe in case the system was hibernated. 9.Winloader loads drivers that are set to start at boot and then transfers the control to the windows kernel.

Benefits of virtualization

1.Faster server provisioning
2.Fewer physical servers means lowering monthly power and cooling costs in the data center.
3.Fewer physical servers means less data center floor space required.
4.Increase uptime with vmotion,svmotion,fault tolerance, high availability, and distributed resource scheduling etc
5.Better utilization of computing resources.Multiple apps and OS in single physical server.
6.No hardware dependency.
7.Easy and flexible infrastructure management

USB and VMware ESX

USB devices are not supported for ESX 4.0 and below.Use parallel port or Digi International has developed AnywhereUSB Remote I/OConcentrator, which utilizes USB over IP Technology.

ESX 4.1 does support USB controllers.ESX 4.1 supports USB device passthrough- Add USB controller and a USB device.
One virtual USB controller per VM.
Per VM max 20 USB devices.

Difference between Vmotion and SVmotion

Vmotion - move from one host to other, disk remains same.
SVmotion - move from one disk to other, host remains same.

Thin provisioning vs Thick provisioning

Thin provisioning  - In this format, the size of the VDMK file occupies on the datastore only the size of how much it is used. For example, if you create a 500GB virtual disk, and place 100GB of data in it, the VMDK file will be 100GB in size in the disk.

Thick provisioning  - If you create a 500GB virtual disk, and place 100GB of data in it, still the VMDK will appear to be 500 GB at the datastore filesystem, but contains only 100GB of data on disk.