With the release of VMware vSphere 4.1, VMware made available the vStorage APIs for Array Integration (VAAI). The VAAI can offload specific storage operations to compliant storage hardware, which results in less CPU, memory and storage fabric bandwidth consumption.
Chad Sakac who is Vice President VMware Technology Alliance at EMC wrote a blog post in July detailing what the impact of using the VAAI means for normal operations and what the benefits are in terms of performance improvements.
"…Just one example (of many)… using the Full Copy API:
- We reduced the time for many VMware storage-related tasks by 25% or more (in some cases up to 10x)
- We reduced the amount of CPU load on the ESX host and the array by 50% or more (in some cases up to 10x) (by reducing the impact during the operation and reducing the duration) for many tasks.
- We reduced the traffic on the network by 99% for those tasks. Yes you read that right, 99%. During these activities (storage vmotion is what we used in the example), so much storage network traffic can be so heavy (in the example 240MBps worth of traffic), it impacts all the other VMs using the storage network and storage arrays.
And like Intel VT with vSphere 4, these improvements just “appear” for customers using vSphere 4.1 and storage arrays that support these new hardware acceleration offloads…"