vStorage API for Array Integration (VAAI) improves ESXi host utilization by offloading storage-related tasks to the Dell Unity system. Because these tasks are processed by the array, the ESXi host’s CPU, memory, and network utilization is reduced. For example, an operation such as provisioning full clones from a template VM can be offloaded to Dell Unity storage. The Dell Unity system 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 Dell Unity storage:
Block:
- Atomic Test and Set (ATS): This enables arrays to perform locking at a block level of a LUN, instead of the whole LUN. This is also known as Hardware-Assisted Locking.
- Block Zero: This enables arrays to zero out a large number of blocks to speed up virtual machine provisioning. This is also known as Hardware-Assisted Zeroing.
- Full Copy: This 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 also known as Hardware-Assisted Move.
- Thin Provisioning: This enables arrays to reclaim unused blocks on a thin LUN. This is also known as Dead Space Reclamation.
File:
- Fast File Clone: This enables the creation of virtual machine snapshots to be offloaded to the array.
- Full File Clone: This enables the offloading of virtual-disk cloning to the array.
- Reserve Space: This enables provisioning virtual disks using the Thick Lazy and Eager Zeroed options over NFS.