Dell Unity: What are VVOLS

Virtual Volumes (vVols): A VMware storage framework which allows VM data to be stored on individual volumes. This allows for data services to be applied at a VM-granularity and Storage Policy Based Management (SPBM).

For a storage array to support vVols, its implementation must address the control path and the data path.

The control path is essentially the communication channel between the vCenter Server and the storage array. The storage array is responsible for advertising the capabilities of the storage presented to the ESXi hosts. The Storage Policy-Based Management (SPBM) leverages this information to create and enforce storage policies applied to VMs. Implementation of the control path involves support for VASA 2.0.

The data path is responsible for the I/O traffic. Data is ultimately stored on a physical device on the storage array. When VMs are reading or writing data to the vVols (whether it be the configuration, swap space, snapshot, or VMDK), the Protocol Endpoints must bind the path between the VM and the location on the physical device in the storage array.

• Unity's VASA Provider is embedded in the controller. That means there is no need for a separate host to manage in a vVol environment. That also means that the VASA Provider can take advantage of the inherent high availability feature of the Unity system. Unity is a dual-controller system, if controller A goes down, controller B can take over thus the VASA connection is highly available. The virtualization administrator enters the management IP of the Unity system along with the supporting account credentials to register the Unity VASA Provider on vCenter.
• Unity supports NAS and SAN connectivity for vVols. That means administrators have the flexibility to provision vVol Datastores on vSphere over NFS, iSCSI, or Fibre Channel. Protocol Endpoints are the NAS Server interfaces, iSCSI initiators, and Fibre Channel ports zoned to the ESXi hosts. The workflow to set up the vVol environment on the Unity system is well integrated into the re-designed array element manager, Unisphere. The process of configuring Capability Profiles, Storage Containers, and presenting them to ESXi hosts are streamlined and easy to use. I will get into the configuration process further down

A Storage Container is the actual repository where data resides. In Unity, a Storage Container consists of one or more storage pools. Each storage pool represents a mixture of drives (for example, Flash, SAS, NL-SAS) with supporting data services (for example, storage tiering). The combination of drives and data services that defines the pool is encapsulated in a Capability Profile. In Unity, a Storage Container can have multiple Capability Profiles. The direct benefit that a virtualization administrator gets from this feature is management simplification. That leads to time saved and redirected to other things. Why is that? In the traditional paradigm of LUNs and file systems presented to the ESXi hosts, each of those storage objects represented a single Capability Profile. Usually, an administrator is not provisioning all the VMs with the same Capability Profile. Engineering wants Capability Profile A. Finance wants Capability Profile B. Marketing wants Capability Profile C. For each unique Capability Profile, it is one or more LUNs or file systems to support it. After a while, that is a lot of storage objects to manage.

With Unity Storage Container, an administrator can conceivably have just one Container for all these different Capability Profiles. At the very least, they can consolidate a few Capability Profiles and significantly reduce the amount of storage objects to manage. Thus, it is management simplification. Less headaches, less time to manage.

Besides that, what is the actual capabilities Unity can advertise to vCenter?

• Data services: Snapshots and Clones (they are not exposed in the Capability Profile but when snapshots or clones are requested on vCenter, the operations offloads to Unity over VASA)
• Drive types: Indicates the types of drives the storage pool contains
• RAID types: Indicates RAID protection of the storage pool
• FAST Cache: It is a Boolean value to indicate whether FAST Cache is enabled for the storage pool
• Tiering Policy: If FAST VP is enabled, there is a storage tiering policy assigned to the storage pool
• Usage tag: Storage administrators can assign custom tags to the Capability Profile to indicate preferred uses of the storage pool (for example, workloads, applications)
• Service Level: Predefined descriptors to translate the Drive and RAID types of the storage pool into an indicator of service level, but not a service level objective.