Using VAAI to boost storage performance
Various storage functions, such as cloning and snapshots, are performed more efficiently by the storage array (target) than by a host (initiator). In a virtualized environment, since virtual disks are files on VMFS and disk arrays cannot interpret the VMFS on-disk data layout; you cannot leverage hardware functions on a per-VM or per-virtual disk (file) basis.
The vStorage APIs for Array Integration (VAAI) are a set of new protocol interfaces between ESXi and storage arrays, and new application programming interfaces in the VMkernel. Using a small set of primitives (fundamental operations) that can be issued to the array using these interfaces, ESXi is able to improve its offering of storage services.
The fundamental operations are:
Atomic test & set (ATS) – new locking mechanism
Clone blocks/full copy/XCOPY
Zero blocks/write same
The goal of VAAI is to help storage vendors provide hardware assistance to speed up VMware I/O operations that are more efficiently...
