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vVols User Guide: Migrating VMs to vVols

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Storage vMotion can migrate VMs from VMFS, NFS, or Raw Device Mappings (RDMs) to vVols.

Migrating a VMFS or NFS-based VM to a vVol-based VM

From the Web Client VMs and Templates inventory pane, right-click the VM to be migrated and select Migrate from the dropdown menu to launch the Migrate wizard.

vvol migrate 01.png
vSphere View: Web Client Migrate Command

Select Change Storage Only to migrate the VM’s storage, or Change both compute resource and storage to migrate both storage and compute resources.

vvol migrate 02.png
vSphere View: Selecting Storage-only Migration

In the ensuing Select storage step, select a vVol datastore as a migration target. Optionally, select a storage policy for the migrated VM to provide additional features. (The section titled Storage Policy Based Management describes storage policies.)

Click Finish (not visible in vSphereView 135) to migrate the VM. If original and target datastores are on the same array, the array uses XCOPY to migrate the VM. FlashArray XCOPY only creates metadata, so migration is nearly instantaneous.

If source and target datastores are on different arrays, VMware uses reads and writes, so migration time is proportional to the amount of data copied.

When migration completes, the VM is vVol-based. Throughout the conversion, the VM remains online.

vvol migrate 03.png
vSphere View: Select Storage Policy

The array view below shows a migrated VM’s FlashArray volume group.

vvol migrate 04.png
Array View: GUI View of a Migrated VM (Volume Group)

Migration of a VM with VMDK Snapshots

Migrating a VM that has VMware managed snapshots is identical to the process described in the preceding subsection. In a VMFS or NFS-based VM, snapshots are VMDK files in the datastore that contain changes to the live VM. In a vVol-based VM, snapshots are FlashArray snapshots.

Storage vMotion automatically copies a VM’s VMware VMFS snapshots. ESXi directs the array to create the necessary data vVols, copies the source VMDK files to them and directs the array to take snapshots of them. It then copies each VMFS-based VMware snapshot to the corresponding data vVol, merging the changes. All copying occurs while the VM is online.

BEST PRACTICE: Only virtual hardware versions 11 and later are supported. If a VM has VMware-managed VMFS-based memory snapshots and is at virtual hardware level 10 or earlier, delete the memory snapshots prior to migration. Upgrading the virtual hardware does not resolve this issue. Refer to VMware’s note here

Migrating Raw Device Mappings

A Raw Device Mapping can be migrated to a vVol in any of the following ways:

  • Shut down the VM and perform a storage migration. Migration converts the RDM to a vVol.
  • Add to the VM a new virtual disk in a vVol datastore. The new virtual disk must be of the same size as the RDM and located on the same array. Copy the RDM volume to the vVol, redirect the VM’s applications to use the new virtual disk, and delete the RDM volume.

For more information, refer to the blog post https://www.codyhosterman.com/2017/11/moving-from-an-rdm-to-a-vvol/