ESX Configuration Guide

Turn off Hardware Acceleration

If your storage devices do not support the hardware acceleration functionality, you can turn it off by using the vSphere Client advanced settings.

As with any advanced settings, before disabling the hardware acceleration, consult with the VMware support team.

Procedure

1In the vSphere Client inventory panel, select the host.

2Click the Configuration tab, and click Advanced Settings under Software.

3 Click VMFS3 and change the value in the VMFS3.HardwareAcceleratedLocking field to zero.

4Click DataMover and change the values in each of the following fields to zero:

nDataMover.HardwareAcceleratedMove

nDataMover.HardwareAcceleratedInit

5 Click OK to save your changes.

Thin Provisioning

When you create a virtual machine, a certain amount of storage space on a datastore is provisioned or allocated to the virtual disk files.

By default, ESX offers a traditional storage provisioning method during creation in which you estimate how much storage the virtual machine will need for its entire life cycle, provision a fixed amount of storage space to its virtual disk, and have the entire provisioned space committed to the virtual disk. A virtual disk that immediately occupies the entire provisioned space is called a thick disk. Creating virtual disks in thick format can lead to underutilization of datastore capacity, because large amounts of storage space, pre-allocated to individual virtual machines, might remain unused.

To help avoid over-allocating storage space and save storage, ESX supports thin provisioning, which lets you, in the beginning, use just as much storage capacity as currently needed and then add the required amount of storage space at a later time. Using the ESX thin provisioning feature, you can create virtual disks in a thin format. For a thin virtual disk, ESX provisions the entire space required for the disk’s current and future activities, but commits only as much storage space as the disk needs for its initial operations.

Chapter 9 Managing Storage

About Virtual Disk Formats

When you perform certain virtual machine management operations, such as create a virtual disk, clone a virtual machine to a template, or migrate a virtual machine, you can specify a format for the virtual disk file.

The following disk formats are supported. You cannot specify the disk format if the disk resides on an NFS datastore. The NFS server determines the allocation policy for the disk.

Create Thin Provisioned Virtual Disks

When you need to save storage space, you can create a virtual disk in thin provisioned format. The thin provisioned virtual disk starts small and grows as more disk space is required.

This procedure assumes that you are creating a typical or custom virtual machine using the New Virtual Machine wizard.

Prerequisites

You can create thin disks only on the datastores that support thin provisioning. If a disk resides on an NFS datastore, you cannot specify the disk format because the NFS server determines the allocation policy for the disk.

Procedure

uIn the Create a Disk dialog box, select Allocate and commit space on demand (Thin Provisioning).

A virtual disk in thin format is created. If you do not select the Thin Provisioning option, your virtual disk will have the default thick format.

What to do next

If you created a virtual disk in the thin format, you can later inflate it to its full size.

View Virtual Machine Storage Resources

You can view how datastore storage space is allocated for your virtual machines.

Procedure

1 Select the virtual machine in the inventory.

2Click the Summary tab.

ESX Configuration Guide

3Review the space allocation information in the Resources section.

n Provisioned Storage – Shows datastore space guaranteed to the virtual machine. The entire space might not be used by the virtual machine if it has disks in thin provisioned format. Other virtual machines can occupy any unused space.

n Not-shared Storage – Shows datastore space occupied by the virtual machine and not shared with any other virtual machines.

n Used Storage – Shows datastore space actually occupied by virtual machine files, including configuration and log files, snapshots, virtual disks, and so on. When the virtual machine is running, the used storage space also includes swap files.

Determine the Disk Format of a Virtual Machine

You can determine whether your virtual disk is in thick or thin format.

Procedure

1Select the virtual machine in the inventory.

2Click Edit Settings to display the Virtual Machine Properties dialog box.

3Click the Hardware tab and select the appropriate hard disk in the Hardware list.

The Disk Provisioning section on the right shows the type of your virtual disk, either Thin or Thick.

4Click OK.

What to do next

If your virtual disk is in the thin format, you can inflate it to its full size.

Convert a Virtual Disk from Thin to Thick

If you created a virtual disk in the thin format, you can convert it to thick.

Procedure

1Select the virtual machine in the inventory.

2Click the Summary tab and, under Resources, double-click the datastore for the virtual machine to open the Datastore Browser dialog box.

3Click the virtual machine folder to find the virtual disk file you want to convert. The file has the .vmdk extension.

4Right-click the virtual disk file and select Inflate.

The virtual disk in thick format occupies the entire datastore space originally provisioned to it.

Handling Datastore Over-Subscription

Because the provisioned space for thin disks can be greater than the committed space, a datastore oversubscription can occur, which results in the total provisioned space for the virtual machine disks on the datastore being greater than the actual capacity.

Over-subscription can be possible because usually not all virtual machines with thin disks need the entire provisioned datastore space simultaneously. However, if you want to avoid over-subscribing the datastore, you can set up an alarm that notifies you when the provisioned space reaches a certain threshold.

For information on setting alarms, see the vSphere Datacenter Administration Guide.

If your virtual machines require more space, the datastore space is allocated on a first come first served basis. When the datastore runs our of space, you can add more physical storage and increase the datastore.