VMware® Virtual SAN™ is a highly efficient technology to build-up cost effective storage solutions in SDDC. Virtual SAN is gaining lot of momentum, and its benefits and technology aspects are very popular in the domain. VSAN Datastore is a logical volume by aggregating all magnetic disks those are locally attached to each host in the VMware vSphere Cluster. Even though, we can use a VSAN Datastore to stage any kind of Virtual Machines and Disk Files, there are additional benefits if we choose to deploy Horizon View Desktops. Here the highlight is that, VSAN becomes a potential use case for Horizon View, along with View Storage Accelerator (VSA).
So, Why VSAN is a better choice for View with VSA ?
The ‘low risk’ factor
In VMware Horizon View, Virtual Desktops are identical VMs deployed from a common template, and it shares most of the system files and contents. Only user data part is differently stored, in case of dedicated assignment. Therefore, the potential risk that can happen by losing such VMs are comparatively very low, because such desktop can be easily re-provisioned from the same master VM template within minutes, and if required user data can made available to those virtual machines separately via persona, persistent disks etc.
View Storage Accelerator feature (using vSphere Content Based Read Cache) will greatly eliminate any performance bottleneck with VSAN Datastore read IOPS, especially during large-scale deployment. VSA can eliminate all the duplicate read ops based on content based caching, and that provides maximum performance on large number of virtual machines with identical consents. “Large number of Virtual machines with identical contents” – That typically happens or applicable within a Virtual Desktop Infrastructure, such as Horizon View Desktop deployments
The Ultimate Use Case
So both the above factors together makes the Smart choice, that is, VSAN + VIEW + VSA. I’ll throw some lights on this concept and How these benefits are achieved; using below diagram:
Efficient Storage Policy-Based Management : View Desktops are Virtual machines with multiple disk files and some of the disk file can contain unique information, such as persistent disk containing User Data. By leveraging Virtual SAN, we can define virtual machine storage requirements, such as performance and availability, in the form of a policy. With ‘Storage Policy-Based Management’ those policy requirements are then pushed down to the Virtual SAN layer when a virtual machine is being provisioned. This way Virtual Desktop VMs’ virtual disks are distributed across the Virtual SAN datastore to meet the availability and performance requirements. Here we can have different storage profiles that control the requirements wisely and efficiently, in other words, we can make sure that, relevant and crucial disk files distributed for availability matter, whereas disks those are shared across Virtual Desktops are distributed for performance matter.
Better Performance through Content Based Read Cache: As articulated in the above diagram, the VSAN Datastore is an aggregate volume of each hosts’s local storage. All read-write operations are cached by Solid State Disks (SSDs). The possible read IOPS bottleneck is from SSD to the Hyperviosr, and that can include a 10G Ethernet channel. This is based on the storage policy and object distribution across VSAN nodes. Offloading these read IOPS plays a vital role in large-scale, by improving VM performance and eliminating boot storm overheads. These benefits are more visible for View Desktops, especially for linked clone desktops because, common disk files are utilized heavily for read operations. Since the majority of the contents, for which the read-request are being issued, are identical in View Desktops, those read operations are completely offloaded from the VSAN layer, and directly served from the host cache. This way the performance of virtual desktops are improved, and at the same time, overheads to VSAN datastore is reduced; through the CBRC contribution of View Storage Accelerator (VSA)
Interestingly there are additional benefits that is exclusive to VSAN and VIEW. Let me share two of them.
- Horizon View needs a costly rebalance operation when conventional storage need to added or migrated. Such requirements will be minimal while hosting the View Desktops on a VSAN Datastore.
- Horizon View automatically creates the best suited VSAN storage profiles for each disk types for optimum redundancy and performance.
So let me conclude by asking you to think about this smart use case; Virtual SAN, Horizon View Desktops, and View Storage Accelerator.
- Comparing VMware VSA & VMware Virtual SAN
- View Storage Accelerator – White Paper
- What’s New in VMware® Virtual SAN™