In this article we will look in some detail at the new features for offloading storage workloads to the SAN array. This is called VAAI – vStorage APIs for Array Integration and enables the ESXi host to hand over some work to the SAN which the SAN array might be best at doing.

VAAI was introduced in vSphere 4.1 and had three offload features, called primitives, and in 5.0 another option was added for VMFS. We access the VMFS file system by block based methods, i.e. Fibre Channel or iSCSI and as we shall see this could lead to large performance improvements especially for iSCSI. In this first article we will study one of the most useful VAAI primitives.

Clone Blocks / Full Copy / XCOPY (different names for the same feature/primitive)

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