6.5.1

Table Of Contents
n
Hardware assisted locking, also called atomic test and set (ATS). Supports discrete virtual machine
locking without use of SCSI reservations. This operation allows disk locking per sector, instead of the
entire LUN as with SCSI reservations.
Check with your vendor for the hardware acceleration support. Certain storage arrays require that you
activate the support on the storage side.
On your host, the hardware acceleration is enabled by default. If your storage does not support the
hardware acceleration, you can disable it.
In addition to hardware acceleration support, ESXi includes support for array thin provisioning. For
information, see ESXi and Array Thin Provisioning.
Disable Hardware Acceleration for Block Storage Devices
On your host, the hardware acceleration for block storage devices is enabled by default. You can use the
vSphere Web Client advanced settings to disable the hardware acceleration operations.
As with any advanced settings, before you disable the hardware acceleration, consult with the VMware
support team.
Procedure
1 Browse to the host in the vSphere Web Client navigator.
2 Click the Configure tab.
3 Under System, click Advanced System Settings.
4 Change the value for any of the options to 0 (disabled):
n
VMFS3.HardwareAcceleratedLocking
n
DataMover.HardwareAcceleratedMove
n
DataMover.HardwareAcceleratedInit
Managing Hardware Acceleration on Block Storage Devices
To integrate with the block storage arrays, vSphere uses the ESXi extensions called Storage APIs - Array
Integration (VAAI). With this integration, vSphere can use the array hardware operations.
In the vSphere 5.x and later releases, these extensions are implemented as the T10 SCSI commands. As
a result, with the devices that support the T10 SCSI standard, your ESXi host can communicate directly
and does not require the VAAI plug-ins.
If the device does not support T10 SCSI or provides partial support, ESXi reverts to using the VAAI plug-
ins, installed on your host. The host can also use a combination of the T10 SCSI commands and plug-ins.
The VAAI plug-ins are vendor-specific and can be either VMware or partner developed. To manage the
VAAI capable device, your host attaches the VAAI filter and vendor-specific VAAI plug-in to the device.
For information about whether your storage requires VAAI plug-ins or supports hardware acceleration
through T10 SCSI commands, see the VMware Compatibility Guide or contact your storage vendor.
vSphere Storage
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