Home > Storage > PowerMax and VMAX > Storage Admin > Dell PowerMax and VMware vSphere Configuration Guide > VMware vSphere Storage API for Array Integration
Storage APIs for Array Integration is an API for storage partners to leverage that permits certain functions to be delegated to the storage array, thus greatly enhancing the performance of those functions. Dell currently offers four storage integrations as part of VAAI: Full Copy, Block Zero, Hardware-assisted locking, and UNMAP. VAAI, by default, provides the ability to offload specific storage operations to the PowerMax to increase both overall system performance and efficiency.
The primitive that will be covered here is hardware-accelerated Full Copy as it is this functionality that enables the offloading of VMware clones to the array.[22] The UNMAP primitive was addressed in Dead Space Reclamation (UNMAP). Note that the Full Copy primitive (SCSI command XCOPY) has not been ported over to NVMeoF and therefore software copy will be used in those instances.
When a customer desires to clone a single or a few virtual machines or move a virtual machine from one datastore to another, using TimeFinder adds unnecessary complexity. Using VAAI in these cases, in essence, does what TimeFinder does, just on a more granular scale. The following section will cover VAAI, and in particular Full Copy, in more detail.
The time it takes to deploy or migrate a virtual machine will be greatly reduced by use of the Full Copy primitive, as the process for data migration is entirely executed on the storage array and not on the ESXi server. The host simply initiates the process and reports on the progress of the operation on the array. This decreases overall traffic on the ESXi server. In addition to deploying new virtual machines from a template or through cloning, Full Copy is also utilized when doing a Storage vMotion. When a virtual machine is migrated between datastores on the same array the live copy is performed entirely on the array.
Not only does Full Copy save time, but it also saves server CPU cycles, memory, IP and SAN network bandwidth, and storage front-end controller IO. This is due to the fact that the host is relieved of the normal function it would serve of having to read the data from the array and then write the data back down to the array. That activity requires CPU cycles and memory as well as significant network bandwidth. Figure 162 provides a graphical representation of Full Copy.
The VAAI primitives are enabled by default on the supported arrays and do not require any user intervention. The primitive, however, can be disabled through the ESXi server if desired. Using the vSphere Client, Full Copy can be disabled or enabled by altering the setting, DataMover.HardwareAcceleratedMove, in the ESXi server advanced settings under DataMover. Figure 163 shows the setting in the vSphere Client.