With hardware acceleration, your host can integrate with block storage devices, Fibre Channel or iSCSI, and use certain storage array operations.
ESXi hardware acceleration supports the following array operations:
Full copy, also called clone blocks or copy offload. Enables the storage arrays to make full copies of data within the array without having the host read and write the data. This operation reduces the time and network load when cloning virtual machines, provisioning from a template, or migrating with vMotion.
Block zeroing, also called write same. Enables storage arrays to zero out a large number of blocks to provide newly allocated storage, free of previously written data. This operation reduces the time and network load when creating virtual machines and formatting virtual disks.
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 Array Thin Provisioning and VMFS Datastores.