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Storage APIs for Array Integration (VAAI) is an API for storage partners to leverage. It permits certain functions to be delegated to the storage array, thus greatly enhancing the performance of those functions. Dell offers four storage integrations as part of VAAI:
VAAI, by default, enables offloading specific storage operations to the PowerMax to increase both overall system performance and efficiency.
The primitive that is covered here is hardware-accelerated Full Copy. This functionality enables the offloading of VMware clones to the array. The UNMAP primitive was addressed in Dead Space Reclamation (UNMAP).
Note: For more information about other Storage APIs, including ATS and ATS heartbeat, see Using VMware vSphere Storage APIs for Array Integration with Dell PowerMax.
The Full Copy primitive (SCSI command XCOPY) has not been ported over to NVMeoF. Software copy is used in those instances.
When a customer wants to clone one or a few virtual machines, or move a virtual machine from one datastore to another, TimeFinder adds unnecessary complexity. Using VAAI in these cases, does what TimeFinder does on a more granular scale. The following section covers VAAI, and in particular Full Copy, in more detail.
Using the Full Copy primitive greatly reduces the time that it takes to deploy or migrate a virtual machine. The process for data migration is entirely performed on the storage array and not on the ESXi server. The host initiates the process and reports on the progress of the operation on the array. This operation decreases overall traffic on the ESXi server. In addition to deploying new virtual machines from a template or through cloning, Full Copy is also used 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 I/O. This efficiency is because the host is relieved of its normal function of reading the data from the array and then writing it back down to the array. That activity requires CPU cycles, memory, and significant network bandwidth. Figure 147 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 wanted. Full Copy can be disabled or enabled by altering the DataMover.HardwareAcceleratedMove setting in the vSphere Client. It is in the ESXi server advanced settings under DataMover. Figure 148 shows the setting in the vSphere Client.