White and Fluffy (All things virtual)

vSphere APIs Array Integration (VAAI) July 2, 2012

Storage APIs is a family of APIs used by third-party hardware, software, and storage providers to develop components that enhance several vSphere features and solutions.

Let’s start with the first one

VMware vSphere® Storage APIs – Array Integration (VAAI)

These are a set of protocol interfaces and VMkernel APIs between VMware vSphere® ESXi and storage arrays.

In a virtualized environment, virtual disks are sometimes located on a VMware vSphere® VMFS datastore. Disk arrays cannot interpret the VMFS datastore’s on-disk data layout, so the VMFS datastore cannot leverage hardware functions per virtual machine or per virtual disk file. The goal of VAAI is to help storage vendors provide hardware assistance to accelerate I/O operations that are more efficiently accomplished in the storage hardware. Think about all that processing that the array can provide.VAAI plug-ins can improve data transfer performance and are transparent to the end user.

In VMware vSphere 5.0, the above functionality is available for storage vendors to take advantage of the following features:

Hardware Acceleration for NAS

This plug-in enables NAS arrays to integrate with vSphere to transparently offload certain storage operations to the array, such as offline cloning (cold migrations, cloning from templates). This integration reduces CPU overhead on the host. Hardware Acceleration for NAS is deployed as a plug-in that is not shipped with ESXi 5.0. This plug-in is developed and distributed by the storage vendor but signed by the VMware® certification program. Array/device firmware enabled for Hardware Acceleration for NAS must use the Hardware Acceleration for NAS features. The storage vendor is responsible for the support of the plug-in.

Array Thin Provisioning  

This feature assists in monitoring disk space usage on thin- provisioned storage arrays. Monitoring this usage helps prevent the condition where the disk is out of space. Monitoring usage also helps when reclaiming disk space. No installation steps are required for the Array Thin Provisioning extensions. Array Thin Provisioning works on all VMFS-3 and VMFS-5 volumes. Device firmware enabled for this API is required to take advantage of the Array Thin Provisioning features. ESXi continuously checks for firmware that is compatible with Array Thin Provisioning. After the firmware is upgraded, ESXi starts using the Array Thin Provisioning features.