Hardware acceleration allows ESXi hosts to integrate with NAS devices and use several hardware operations that NAS storage provides. Hardware acceleration uses VMware vSphere Storage APIs for Array Integration (VAAI) to enable communication between the hosts and storage devices.
The APIs define a set of storage primitives that enable the host to offload certain storage operations to the array. The following list shows the supported NAS operations:
- Full File Clone. Enables NAS device to clone virtual disk files. This operation is similar to the VMFS block cloning, except that NAS devices clone entire files instead of file segments.
- Reserve Space. Enables storage arrays to allocate space for a virtual disk file in thick format.
Typically, when you create a virtual disk on an NFS datastore, the NAS server determines the allocation policy. The default allocation policy on most NAS servers is thin and does not guarantee backing storage to the file. However, the reserve space operation can instruct the NAS device to use vendor-specific mechanisms to reserve space for a virtual disk. As a result, you can create thick virtual disks on the NFS datastore.
- Native Snapshot Support. Allows creation of virtual machine snapshots to be offloaded to the array.
- Extended Statistics. Enables visibility to space usage on NAS devices and is useful for Thin Provisioning.
With NAS storage devices, the hardware acceleration integration is implemented through vendor-specific NAS plug-ins. These plug-ins are typically created by vendors and are distributed as VIB packages through a web page. No claim rules are required for the NAS plug-ins to function.
There are several tools available for installing and upgrading VIB packages. They include the esxcli commands and vSphere Update Manager. For more information, see the vSphere Upgrade and Installing and Administering VMware vSphere Update Manager documentation.