6.7

Table Of Contents
Snapshot-VVol A virtual memory volume to hold the contents of virtual machine memory for
a snapshot. Thick-provisioned.
Other A virtual volume for specific features. For example, a digest virtual volume
is created for Content-Based Read Cache (CBRC).
Example: Types of Virtual Volumes
Typically, a VM creates a minimum of three virtual volumes, data-VVol, config-VVol, and swap-VVol. The
maximum depends on how many virtual disks and snapshots reside on the VM.
For example, the following SQL server has six virtual volumes:
n
Config-VVol
n
Data-VVol for the operating system
n
Data-VVol for the database
n
Data-VVol for the log
n
Swap-VVol when powered on
n
Snapshot-VVol
By using different virtual volumes for different VM components, you can apply and manipulate storage
policies at the finest granularity level. For example, a virtual volume that contains a virtual disk can have a
richer set of services than the virtual volume for the VM boot disk. Similarly, a snapshot virtual volume can
use a different storage tier compared to a current virtual volume.
Virtual Volumes and Thin Provisioning
The Virtual Volumes functionality supports a concept of thin and thick-provisioned virtual disks. However,
from the I/O prospective, implementation and management of thin or thick provisioning by the arrays is
transparent to the ESXi host. ESXi offloads to the storage arrays any functions related to thin
provisioning. In the data path, ESXi does not treat the thin or thick virtual volumes differently.
You select the thin or thick type for your virtual disk at the VM creation time. If your disk is thin and resides
on a VVols datastore, you cannot change its type later by inflating the disk.
Virtual Volumes and Storage Providers
A Virtual Volumes storage provider, also called a VASA provider, is a software component that acts as a
storage awareness service for vSphere. The provider mediates out-of-band communication between
vCenter Server and ESXi hosts on one side and a storage system on the other.
The storage provider is implemented through VMware APIs for Storage Awareness (VASA) and is used to
manage all aspects of Virtual Volumes storage. The storage provider integrates with the Storage
Monitoring Service (SMS), shipped with vSphere, to communicate with vCenter Server and ESXi hosts.
vSphere Storage
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