Chapter 9 Managing Storage

Storage Hardware Acceleration

The hardware acceleration functionality enables your host to offload specific virtual machine and storage management operations to compliant storage hardware. With the storage hardware assistance, your host performs these operations faster and consumes less CPU, memory, and storage fabric bandwidth.

To implement the hardware acceleration functionality, the Pluggable Storage Architecture (PSA) uses a combination of special array integration plug-ins, called VAAI plug-ins, and an array integration filter, called VAAI filter. The PSA automatically attaches the VAAI filter and vendor-specific VAAI plug-ins to those storage devices that support the hardware acceleration.

To view and manage the VAAI filter and VAAI plug-ins available on your host, use the vSphere CLI commands.

For descriptions of the commands, see the vSphere Command-Line Interface Installation and Scripting Guide and the vSphere Command-Line Interface Reference.

Hardware Acceleration Requirements and Benefits

The hardware acceleration functionality works only if you use an appropriate host and storage array combination.

Use the following hosts and storage arrays:

nESX version 4.1 or later.

nStorage arrays that support storage-based hardware acceleration. ESX version 4.1 does not support hardware acceleration with NAS storage devices.

On your host, the hardware acceleration is enabled by default. To enable the hardware acceleration on the storage side, check with your storage vendor. Certain storage arrays require that you explicitly activate the hardware acceleration support on the storage side.

When the hardware acceleration functionality is supported, the host can get hardware assistance and perform the following operations faster and more efficiently:

nMigration of virtual machines with Storage vMotion

nDeployment of virtual machines from templates

nCloning of virtual machines or templates

nVMFS clustered locking and metadata operations for virtual machine files

nWrites to thin provisioned and thick virtual disks

nCreation of fault-tolerant virtual machines

Hardware Acceleration Support Status

For each storage device and datastore, the vSphere Client displays the hardware acceleration support status in the Hardware Acceleration column of the Devices view and the Datastores view.

The status values are Unknown, Supported, and Not Supported. The initial value is Unknown. The status changes to Supported after the host successfully performs the offload operation. If the offload operation fails, the status changes to Not Supported.

When storage devices do not support or provide only partial support for the host operations, your host reverts to its native methods to perform unsupported operations.

VMware, Inc.

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