If you've been planning a virtualization migration over the last few months, there's a good chance that the VMware Virtual Disk Development Kit (VDDK) has come up, and probably at a point in the project where you'd have preferred it didn't. Many migration and data protection tools use VDDK to read and copy virtual disks. Many of our customers report that they can no longer obtain it through the standard public download paths. Having spent a good part of my career as a virtualization administrator and technical architect before moving to the vendor side, I know how unwelcome it is to find that a component you never had to think about is suddenly holding up a project you've already committed to.
The good news: Red Hat offers migration options that do not depend on VDDK.
None of this is unique to one vendor or one tool, because VDDK is used by many migration tools and third-party data protection products. The reason it causes concern is that data transfer is a critical part of any VMware-based VM migration. Planning to move a VM to run on a new platform is one part of the job, and for any migration, how you copy its disk data has a major impact on project duration and each workload's potential downtime. Data transfer is also an area where Red Hat has been expanding customer options over the past year, giving organizations more flexibility when planning migrations to Red Hat OpenShift Virtualization.
2 ways to move VM data without VDDK
For our customers, migration toolkit for virtualization (MTV), the migration tooling for OpenShift Virtualization, includes two built-in data transfer capabilities that can avoid the dependency on VDDK in different circumstances. The first, storage copy offload, was already in place for qualifying environments before the recent change in VDDK availability. The second is a VDDK-independent transfer capability that provides another option to explore for warm and cold VM migration. Both capabilities are part of MTV. Which approach is appropriate depends on your storage environment, workload requirements and migration plans.
Storage copy offload
Red Hat has worked with multiple storage partners on storage copy offload, which uses the storage systems you already have to do the heavy lifting during a VM migration. Traditional migrations move disk data over the IP network, whereas storage copy offload hands that work to the underlying storage array, where it performs the copy internally, so the disk copy doesn't need VDDK and the migration can use significantly less migration-network capacity. MTV 2.11 includes storage copy offload for cold migration, and MTV 2.12 extends storage copy offload to warm migration on supported storage products and configurations.
Storage copy offload is designed for source VMs on block storage connected through iSCSI or Fibre Channel, with the source datastore and target volume on the same supported array. MTV 2.12 supports storage copy offload with products from Hitachi Vantara, NetApp, Pure Storage, Dell, HPE, Infinidat and IBM. Check the exact configuration requirements in MTV 2.12, including the separate migration requirements for any vSAN-backed VMs.
For environments where storage copy offload doesn’t fit, there’s another MTV transfer capability worth exploring.
The VDDK-independent transfer capability
Red Hat is expanding customer choice with a VDDK-independent transfer capability for environments where storage copy offload doesn't apply or doesn't meet a customer's requirements. It provides another option to explore for warm and cold migration. Within two weeks of the change to VDDK public downloads, the first customers were using this capability to continue their migrations.
Working out which path fits
The right approach depends on your storage environment, migration schedule and workload requirements. For qualifying environments, storage copy offload reduces the amount of disk data sent over the migration network.
If VDDK has been a sticking point in your move to OpenShift Virtualization, connect with your Red Hat representative or migration partner to explore the available options and build a plan for your environment. If you’re still evaluating OpenShift Virtualization, the Red Hat OpenShift Migration Advisor provides a no-cost assessment of your VMware environment to help inform your next steps.
