6.7

Each virtual volume is bound to a specific protocol endpoint. When a virtual machine on the host performs
an I/O operation, the protocol endpoint directs the I/O to the appropriate virtual volume. Typically, a
storage system requires just a few protocol endpoints. A single protocol endpoint can connect to
hundreds or thousands of virtual volumes.
On the storage side, a storage administrator configures protocol endpoints, one or several per storage
container. The protocol endpoints are a part of the physical storage fabric. The storage system exports
the protocol endpoints with associated storage containers through the storage provider. After you map the
storage container to a Virtual Volumes datastore, the ESXi host discovers the protocol endpoints and they
become visible in the vSphere Client. The protocol endpoints can also be discovered during a storage
rescan. Multiple hosts can discover and mount the protocol endpoints.
In the vSphere Client, the list of available protocol endpoints looks similar to the host storage devices list.
Different storage transports can be used to expose the protocol endpoints to ESXi. When the SCSI-based
transport is used, the protocol endpoint represents a proxy LUN defined by a T10-based LUN WWN. For
the NFS protocol, the protocol endpoint is a mount point, such as an IP address and a share name. You
can configure multipathing on the SCSI-based protocol endpoint, but not on the NFS-based protocol
endpoint. No matter which protocol you use, the storage array can provide multiple protocol endpoints for
availability purposes.
Protocol endpoints are managed per array. ESXi and vCenter Server assume that all protocol endpoints
reported for an array are associated with all containers on that array. For example, if an array has two
containers and three protocol endpoints, ESXi assumes that virtual volumes on both containers can be
bound to all three protocol points.
Binding and Unbinding Virtual Volumes to Protocol Endpoints
At the time of creation, a virtual volume is a passive entity and is not immediately ready for I/O. To access
the virtual volume, ESXi or vCenter Server send a bind request.
The storage system replies with a protocol endpoint ID that becomes an access point to the virtual
volume. The protocol endpoint accepts all I/O requests to the virtual volume. This binding exists until
ESXi sends an unbind request for the virtual volume.
For later bind requests on the same virtual volume, the storage system can return different protocol
endpoint IDs.
When receiving concurrent bind requests to a virtual volume from multiple ESXi hosts, the storage system
can return the same or different endpoint bindings to each requesting ESXi host. In other words, the
storage system can bind different concurrent hosts to the same virtual volume through different endpoints.
The unbind operation removes the I/O access point for the virtual volume. The storage system might
unbind the virtual volume from its protocol endpoint immediately, or after a delay, or take some other
action. A bound virtual volume cannot be deleted until it is unbound.
Virtual Volumes Datastores
A Virtual Volumes (VVol) datastore represents a storage container in vCenter Server and the
vSphere Client.
vSphere Storage
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