Are you wondering why I am still talking about a Hypervisor feature in a time where everyone talk exclusively about Cloud. Some have went as far as describing hypervisors as a commodity. Others will tell you that it does not matter which hypervisor you choose for your cloud, as long as you choose the best Cloud Management platform available.
As you can tell from the topic of this article, I strongly disagree with this approach. It’s very difficult for your Cloud Management platform to make up for the flows of your hypervisor. In most cases, it is not even a goal of your Cloud Management Platform to make up for these hypervisor flows. Your Virtual Machines will always run on your hypervisor, and how well they perform is highly controlled by which hypervisor you choose and the infrastructure below it rather than by how well your Cloud Management Platform does. The reliability and efficiency of the hypervisor running your cloud of choice is a determining factor of your cloud availability and efficiency.
Now that I have set context of why a Hypervisor choice is important to your cloud, I wanted to discuss a particular VMware vSphere feature that I have noticed many customers over looked when trying to build their Private Cloud. I have even seen this over looked by some of VMware vCloud Air Network Partners (Providers of VMware based public cloud) prior to arriving onsite. I am hoping this will get you not only to pay a close attention to which hypervisor you will, but pay a close a tension of how you tune it and utilize advanced hypervisor features to make up the best of your cloud.
I get onsite and work with customer of all kinds of scale on building their Cloud Management Platform of choice being vCloud Director, vRealize Automation, or VMware Integrated OpenStack. After deciding on their Cloud Management Platform, how it will be setup, and understanding their use case. I have made it a normal practice to look at their Virtual Infrastructure design to guide them on design decisions and feature tuning to best complement their being built cloud. I have developed this practice after seeing customers complaining of their cloud management platform not performing to their liking due to bad design or misconfiguration of their Virtual Infrastructure/Hypervisor.
A feature that has been consistently missed is VMware vSphere Storage APIs Array Integration (VAAI). vStorage APIs for Array Integration is a feature introduced in ESXi/ESX 4.1 that provides hardware acceleration functionality. It enables your host to offload specific virtual machine and storage management operations to compliant storage hardware. With the storage hardware assistance, your host performs these operations faster and consumes less CPU, memory, and storage fabric bandwidth. As one of the main reasons behind adopting cloud in the enterprise is agility being able to perform such operations faster is key.
VAAI provides the following functionalities:
- Clone Blocks/Full Copy/XCOPY, which is used to copy or migrate data within the same physical array
- Atomic Test & Set (ATS), which is used during creation and locking of files on the VMFS volume
- Zero Blocks/Write Same, which is used to zero-out disk regions
- Thin Provisioning in ESXi 5.x and later hosts, which allows the ESXi host to tell the array when the space previously occupied by a virtual machine (whether it is deleted or migrated to another datastore) can be reclaimed on thin provisioned LUNs
- Block Delete in ESXi 5.x and later hosts, which allows for space to be reclaimed using the SCSI UNMAP feature. For more information on Block Delete/SCSI UNMAP
The Clone Blocks/Fully Copy/XCOPY feature will allow you to deploy your VMs much faster, as rather than having to copy the bits over your IP network, it will be copied in hardware within the storage system itself. In return increasing your agility of delivering these VMs. I have seen 4-5x faster cloning when enabling VAAI in the past, which is greatly desirable in a cloud environment.
The rest of the VAAI functionalities will improve the performance of your workload operating in your private Cloud or a VMware based public cloud that utilize VAAI. From being able to zero out bits quicker to using a better datastore locking mechanism, all of these VAAI features can add a dramatic performance improvement to your workload that can be appreciated by your cloud users.
In conclusion, the hypervisor you use and the features you enable and how you tune your hypervisor is still a critical piece of how agile, high performance, and reliable your cloud offering will be. VMware vSphere Storage APIs Array Integration (VAAI) provides functionality that can dramatically improve the agility of your Cloud Management Platform as well increase the performance of your workload and should not be overlooked in any vSphere based cloud.
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