How to Add a Hard Disk to a Virtual Machine in VMware ESX Server

When you add a hard disk to a virtual machine, you can create a new virtual disk, add an existing virtual disk, or add a mapped SAN LUN.

Procedure:
1. Start the Add Hardware wizard.

2. Select Hard Disk, and click Next.

3. Select the type of storage for the virtual machine’s disk, and click Next. You can store virtual machine data in a new virtual disk, an existing virtual disk, or a Mapped SAN LUN. A virtual disk, which appears as a single hard disk to the guest operating system, is composed of one or more files on the host file system. Virtual disks can easily be copied or moved on the same host or between hosts.

4. If you selected Create a new virtual disk, do the following:
a. Enter the disk capacity.
b. Select the location as either Store with the virtual machine or Specify a datastore.
c. If you selected Specify a datastore, browse for the datastore location, and click Next. Continue with Step 7.

5. If you selected an existing disk, browse for the disk file path and click Next

6. If you selected Mapped SAN LUN:
a. Select the LUN that you want to use for the raw disk, and click Next.
b. Select a datastore and click Next.
c. Select the compatibility mode: physical to allow the guest operating system to access the hardware directly or virtual to allow the virtual machine to use VMware snapshots and other advanced functions. Click Next.

7. Specify the virtual device node.

8. Set virtual disk mode options:
a. Select Independent to make the disk independent. Independent disks are not affected by snapshots.
b. If you selected Independent, select one of the two modes for independent disks:
 Persistent – The disk operates normally except that changes to the disk are permanent even if the virtual machine is reverted to a snapshot.
 Nonpersistent – The disk appears to operate normally, but whenever the virtual machine is powered off or reverted to a snapshot, the contents of the disk return to their original state. All later changes are discarded.

9. Click Next.

10. Review the information, and click Finish.