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VMware Virtual Volumes (VVOLs) feature marks an important shift in virtual machine storage. Typically, a vSphere administrator approaches storage by providing disks, arrays, interfaces, protocols and other components; workloads are placed on those components which must provide adequate capabilities and performance. It can get complicated to unravel issues if VMs don't get the required speeds, leaving administrators shuffling workloads to different areas to get as close as possible to the storage characteristics needed.
VVOLs are part of the policy based management technology that is turning this paradigm around. Yes, we still have the same kinds of storage and network components, but the evolution of virtualized infrastructures allows the physical components to present their unique features and capabilities to a software layer. The workload -- application or service -- can see which resources meet the desired requirements, and then place the workload onto resources that will yield the best performance, reliability and so on.
Let's look at this a little more specifically. Today, we put a workload on a logical unit number (LUN) located on a storage array; the performance of that workload is limited by the characteristics of the LUN and its underlying array. VMware Virtual Volumes allows individual VMs to carry storage policies, and VMs can then tell the array what policies are needed. The VM will be stored, cloned, snapshotted or backed up to storage instances that can best accommodate the policies for that VM.
Although vSphere 6 is compatible with VVOLs, it's critical to note that not all vSphere 6 features are compatible with VVOLs. For example, basic vSphere 6 functionality such as thin provisioning, vMotion, storage vMotion, snapshots, clones, high availability, Virtual SAN and linked clones are compatible with VVOLs. However, advanced vSphere 6 capabilities such as NFS v4.1, fault tolerance, array-based replication, raw device mapping and Microsoft failover clustering do not support VVOLs.
In addition, tools like vRealize Automation 6.2.x, Horizon 6.1.x and vSphere Replication 6.0.x are compatible with VVOLs. But a wide assortment of VMware offerings such as vCloud Air, NSX for vSphere 6.x, vCloud Director 5.x, SRM 5.x and 6.0.x, and vRealize Operations Manager 6.0.x do not support VVOLs. Administrators should check VMware's Knowledge Base article 2112039 for regular updates on VVOLs feature and product compatibility since this will likely change over time. Even when compatibility is present, it's best to perform due diligence by testing compatibility and performance before rolling out VMware Virtual Volumes in production environments.
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