Virtual Volumes(VVOL)

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.