What is VVOL?
Virtual volumes is a new virtual machine disk management and integration framework that enables array-based operations at the virtual disk level. It makes SAN and NAS storage systems capable of being managed at a virtual machine level. With virtual volumes, most of the data operations are offloaded to the storage arrays.
Virtual volumes eliminate the need to provision and manage large number of LUNs or volumes per host. This reduces operational overahead while enabling scalable data services on a per-virtual machine level.
Storage policy-based management(SPBM) is a key technology that works in conjuction with virtual volumes. This framework provides dynamic resource allocation and management of storage-related services. Administrators can specify a set of storage requirements and capabilities for any particular virtual machine to match service levels required by hosted applications.
To use VVOL storage, you will need vSphere 6.0 or higher and certified array vendor Virtual Volumes software (VASA Provider).
Storage vendors are providing Virtual Volumes integration in different ways.
Key Elements of Virtual Volumes Storage Framework:
1. Protocol Endpoint (PE):
Protocol endpoints are the access points from the hosts to the storage systems, which are created by storage
administrators. All path and policies are administered by protocol endpoints. Protocol Endpoints are compliant with both, iSCSI and NFS. They are intended to replace the concept of LUNs and mount points.
2. Stroage Container :
A storage container is a logical abstraction on to which Virtual Volumes are mapped and stored. Storage containers are setup at the array level and associated with array capabilities.vSphere will map storage containers to VVol Datastores and provide applicable datastore level functionality. The VVol Datastore is a key element and it allows the vSphere Admin to provision VMs without depending on the Storage Admin. Moreover,the VVolDatastore provides logicalabstraction for managing a very large number of Virtual Volumes. This abstraction can be used for better managing multi-tenancy, various departments within a single organization, etc.
3. PE Function:
PE represents the IO access point for a Virtual Volume. When a Virtual Volumeis created, it is not immediately accessible for IO. To Access Virtual Volumes,vSphere needs to issue a “Bind” operation to a VASA Provider (VP),which creates IO access point for a Virtual Volumeon a PE chosen by a VP. A single PE can be the IO access point for multiple Virtual Volumes. “Unbind” Operation will remove this IO access point for a given Virtual Volume.
PEs are associated with arrays. One PE is associated with one array only. An array can be associated with multiple PEs. For block arrays, PEs will be a special LUN. ESX can identify these special LUNs and make sure that visible list of PEs is reported to the VP. For NFS arrays, PEs are regular mountpoints.