vSphere Storage APIs - Array Integration (VAAI) improves ESXi host utilization by offloading storage-related tasks to PowerStore. Because the array processes these tasks, the ESXi host CPU, memory, and network utilization are reduced. For example, an operation such as provisioning full clones from a template VM can be offloaded to PowerStore. PowerStore processes these requests internally, performs the write operations, and returns an update to the ESXi host when the requests are complete.
The following primitives are supported with PowerStore:
- Atomic Test and Set (ATS): Enables arrays to perform locking at the block level of a volume, instead of the whole volume, which enables multiple ESXi hosts to access a volume simultaneously. This is also known as Hardware-Assisted Locking.
- Block Zero: Enables arrays to zero out many blocks, which speeds VM provisioning by accelerating the disk zeroing operation. This is also known as Hardware-Assisted Zeroing or Write Same.
- Full Copy: Enables arrays to make full copies of data within the array without the need for the ESXi host to read and write the data. This is useful when cloning VMs, and it is also known as Hardware-Assisted Move or XCOPY. (XCOPY is not standardized in NVMe specifications, and NVMe/TCP and NVMe/FC do not support Full Copy offload.)
- Thin Provisioning – Unmap: Enables arrays to reclaim unused blocks on a thin LUN. Unmap is also known as Dead Space Reclamation.
- File: These primitives are introduced in PowerStoreOS 3.0 and require installation of the VAAI plug-in on the ESXi hosts.
- Fast File Clone: Enables the creation of virtual machine snapshots to be offloaded to the array.
- Full File Clone: Enables the offloading of virtual-disk cloning to the array.
- Reserve Space: Enables provisioning virtual disks using the Thick Lazy and Eager Zeroed options over NFS.
- Extended Statistics: Enables visibility into space usage on NAS datastores and is especially useful for thin-provisioned datastores.
