VMware Storage vMotion is a component of VMware vSphere™ that provides an intuitive interface for live migration of virtual machine disk files within and across storage arrays with no downtime or disruption in service. Storage VMotion relocates virtual machine disk files from one shared storage location to another shared storage location with zero downtime, continuous service availability and complete transaction integrity. Storage VMotion enables organizations to perform proactive storage migrations, simplify array migrations, improve virtual machine storage performance and free up valuable storage capacity. Storage VMotion is fully integrated with VMware vCenter Server.

Primary Benefits of Storage vMotion

Simplify array migrations and storage upgrades.
The traditional process of moving data to new storage is cumbersome, time-consuming and disruptive. With Storage vMotion, IT organizations can accelerate migrations while minimizing or eliminating associated service disruptions, making it easier, faster and more cost-effective to embrace new storage platforms and file formats, take advantage of flexible leasing models, retire older, hard-to-manage storage arrays and to conduct storage upgrades and migrations based on usage and priority policies. Storage VMotion works with any operating system and storage hardware platform supported by VMware ESX™ and ESXi ™, enabling customers to use a heterogeneous mix of datastores and file formats.

Dynamically optimize storage I/O performance.
Optimizing storage I/O performance often requires reconfiguration and reallocation of storage, which can be a highly disruptive process for both administrators and users and often requires scheduling downtime. With Storage VMotion, IT administrators can move virtual machine disk files to alternative LUNs that are properly configured to deliver optimal performance without the need for scheduled downtime, eliminating the time and cost associated with traditional methods.

Efficiently manage storage capacity.
Increasing or decreasing storage allocation requires multiple manual steps, including coordination between groups, scheduling downtime and adding additional storage. This is then followed by a lengthy migration of virtual machine disk files to the new datastore, resulting in significant service downtime. Storage VMotion improves this process by enabling administrators to take advantage of newly allocated storage in a non-disruptive manner. Storage VMotion can also be used as a storage tiering tool by moving data to different types of storage platforms based the data value, performance requirements and storage costs.

VMware vSphere 5.0 Storage vMotion Enhancements

Storage vMotion in vSphere 5.0 has received multiple enhancements to increase efficiency of the Storage vMotion process, improve overall performance, and enhance supportability. Storage vMotion in vSphere 5.0 now supports the migration of virtual machines with a vSphere Snapshots present, as well as the migration of linked clones.

The enhancements to Storage vMotion include a new and more efficient migration process through the use of new feature called Mirror Mode. Mirror Mode enables a single-pass block copy of the source disk to the destination disk by mirroring I/O’s of copied blocks. Not only has efficiency of Storage vMotion increased but also migration time predictability. Making it easier to plan migrations and reducing the elapsed time per migration.

The Mirror Driver is enabled on a per virtual machine basis and resides within the VMkernel. When the Guest OS of the virtual machine that is undergoing the Storage vMotion initiates a write to an already copied block the Mirror Driver will synchronously mirror this write and wait for both acknowledgements before informing the Guest OS.

Take the Next Step

Learn more about enabling shared storage for virtual machines or find resources and best practices for deploying shared storage for virtual machines.