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VMw a r e St o r a g e VMo t i o n
Storage VMotion allows you to migrate virtual machine disks for running virtual machines from
one storage array to another. This avoids the need to schedule any service disruption or downtime
because of planned storage maintenance or during storage migrations and upgrades. Storage
VMotion was introduced in VMware Infrastructure 3.5, but it supported only the CLI and a lim-
ited number of storage protocols. Storage VMotion in vSphere is now integrated into vCenter and
features several new capabilities:
Includes full support for migrations from one storage vendor to another
•u
Works across NFS, Fibre Channel, and iSCSI storage protocols•u
Includes an option to change the virtual disk format during a Storage VMotion session •u
such as changing a thick to thin virtual disk format, or vice versa.
Storage VMotion in vSphere also features a more efficient migration process. It leverages a
new and more efficient block copy mechanism in the VMkernel instead of using the virtual disk
snapshot method found in the earlier releases of VMware products.
You can use Storage VMotion with thin provisioning to not only migrate a VM from one
data store to another but also reclaim over-provisioned storage space during this process.
Virtual machines often have guest OS virtual disks that are over-provisioned compared to
what they truly need for their current storage requirements. With Storage VMotion, you can
change the virtual disk format from thick to thin and reclaim this over-allocated but unused
storage space (Figure 1.12).
Figure 1.11
VMware vSphere
VMotion types
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