You can add a virtual hard disk to an existing virtual machine, or you can add a hard disk when you customize the virtual machine hardware during the virtual machine creation process. For example, you might need to provide additional disk space for an existing virtual machine with a heavy work load. During virtual machine creation, you might want to add a hard disk that is preconfigured as a boot disk.

During virtual machine creation, a hard disk and a SCSI or SATA controller are added to the virtual machine by default, based on the guest operating system that you select. If this disk does not meet your needs, you can remove it and add a new hard disk at the end of the creation process.

If you add multiple hard disks to a virtual machine, you can assign them to several controllers to improve performance. For controller and bus node behavior, see SCSI and SATA Storage Controller Conditions, Limitations, and Compatibility.

Ensure that you are familiar with configuration options and caveats for adding virtual hard disks. See Virtual Disk Configuration.

Before you add disks greater than 2TB to a virtual machine, see Large Capacity Virtual Disk Conditions and Limitations.

Verify that you have the Virtual machine.Configuration.Add new disk privilege on the destination folder or datastore.

1

Right-click a virtual machine in the inventory and select Edit Settings.

2

(Optional) To delete the existing hard disk, move your cursor over the disk and click the Remove icon.

The disk is removed from the virtual machine. If other virtual machines share the disk, the disk files are not deleted.

3

On the Virtual Hardware tab, select New Hard Disk from the New device drop-down menu and click Add.

The hard disk appears in the Virtual Hardware devices list.

4

Expand New hard disk.

5

(Optional) Type a value for the hard disk and select the units from the drop-down menu.

6

Select the datastore location where you want to store the virtual machine files.

Option

Action

Store all virtual machine files in the same location on a datastore.

a

(Optional) Apply a virtual machine storage policy for the virtual machine home files and the virtual disks from the VM storage policy drop-down menu.

The list shows which datastores are compatible and which are incompatible with the selected virtual machine storage policy.

b

Select a datastore and click Next.

Store all virtual machine files in the same datastore cluster.

a

(Optional) Apply a virtual machine storage policy for the virtual machine home files and the virtual disks from the VM storage policy drop-down menu.

The list shows which datastores are compatible and which are incompatible with the selected virtual machine storage profile.

b

Select a datastore cluster.

c

(Optional) If you do not want to use Storage DRS with this virtual machine, select Disable Storage DRS for this virtual machine and select a datastore within the datastore cluster.

d

Click Next.

Store virtual machine configuration files and disks in separate locations.

a

Click Advanced.

b

For the virtual machine configuration file and for each virtual disk, click Browse and select a datastore or datastore cluster.

c

(Optional) Apply a virtual machine storage policy from the VM storage profile drop-down menu.

The list shows which datastores are compatible and which are incompatible with the selected virtual machine storage policy.

d

(Optional) If you selected a datastore cluster and do not want to use Storage DRS with this virtual machine, select Disable Storage DRS for this virtual machine and select a datastore within the datastore cluster.

e

Click Next.

7

Select the format for the virtual machine's disks and click Next.

Option

Action

Thick Provision Lazy Zeroed

Create a virtual disk in a default thick format. Space required for the virtual disk is allocated during creation. Any data remaining on the physical device is not erased during creation, but is zeroed out on demand at a later time on first write from the virtual machine.

Thick Provision Eager Zeroed

Create a thick disk that supports clustering features such as Fault Tolerance. Space required for the virtual disk is allocated at creation time. In contrast to the flat format, the data remaining on the physical device is zeroed out during creation. It might take much longer to create disks in this format than to create other types of disks.

Thin Provision

Use the thin provisioned format. At first, a thin provisioned disk uses only as much datastore space as the disk initially needs. If the thin disk needs more space later, it can grow to the maximum capacity allocated to it.

8

In the Shares drop-down menu, select a value for the shares to allocate to the virtual disk.

Shares is a value that represents the relative metric for controlling disk bandwidth. The values Low, Normal, High, and Custom are compared to the sum of all shares of all virtual machines on the host.

9

If you selected Custom, type a number of shares in the text box.

10

In the Limit - IOPs box, enter the upper limit of storage resources to allocate to the virtual machine, or select Unlimited.

This value is the upper limit of I/O operations per second allocated to the virtual disk.

11

Accept the default or select a different virtual device node.

In most cases, you can accept the default device node. For a hard disk, a nondefault device node is useful to control the boot order or to have different SCSI controller types. For example, you might want to boot from an LSI Logic controller and share a data disk with another virtual machine that is using a Buslogic controller with bus sharing turned on.

12

(Optional) Select a disk mode and click OK.

Option

Description

Dependent

Dependent disks are included in snapshots.

Independent - Persistent

Disks in persistent mode behave like conventional disks on your physical computer. All data written to a disk in persistent mode are written permanently to the disk.

Independent - Nonpersistent

Changes to disks in nonpersistent mode are discarded when you power off or reset the virtual machine. With nonpersistent mode, you can restart the virtual machine with a virtual disk in the same state every time. Changes to the disk are written to and read from a redo log file that is deleted when you power off or reset.