VAAI and why Storage Admins should know about it (Part 1 of 2)

As a Storage technical specialist, I get the opportunity to talk to customers about new technologies that are intended to make life much simpler. Recently, I have been introducing folks to a technology that was originally introduced in 2008 called Vstorage API for Array Integration or VAAI for short. Often, many people describe it as VMware API's for Array Integration. I dont know (nor do I care) what the real answer is - all I know is that it is a breakthrough technolgy that should be adopted.

So what is it? In a nutshell - VAAI allows one to offload array specific operations from VMware servers to the external storage device. Brilliant! 

This blog is a two part series that I extracted from a document I wrote up . The first part discusses the first primitive - Full Copy Offload. The 2nd part of the blog (next week) will discuss the primitives Block Zeroing and Hardware Assisted Locking.

Enjoy - Raj

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Virtualization administrators are always looking for ways to improve scalability, performance and efficiency of their vSphere infrastructure.  One way to do this is utilizing storage integration with VMware vStorage APIs for Array Integration (VAAI).   VAAI is a set of APIs, or primitives, that allow vSphere infrastructures to offload processing of data related tasks which can burden an ESX server.  Utilizing a storage platform with VAAI enabled, can provide significant improvements in vSphere performance, scalability and availability. 

 In ESX 4.1, that vStorage API for Array Integration includes three basic capabilities or primitives: :

1) Full Copy (aka Hardware Copy offload):

Benefit: considerable boost in system performance and fast completion of copy operations; minimized host processing and network traffic

2) Block Zeroing (aka Write Same)

3)Hardware Assisted Locking (aka Atomic Test & Set): replacement of the SCSI-2 lock/reservation in VMFS 

Benefit: Significantly improved scalability and performance

Full Copy (Copy Offload)

Tasks such as VM provisioning and VM migration are part of the everyday activities of most VMware administrators.  As the virtual environment continues to scale, it is important to keep a watchful eye on the overall impact these activities have on the VMware infrastructure. 

Here, the ESX server is removed from the data path of the data copy when HW copy is enabled.  This greatly increases the speed of these copy functions while reducing impact to the ESX server.

The Benefit: considerable boost in system performance and fast completion of copy operations; minimized host processing and network traffic. Thousands of commands per second and IOPs on the ESX server can be freed up to process other tasks and promote greater scalability.