My first migration from VMware to OpenShift Virtualization worked. It was also painfully slow: one 10 GiB Ubuntu VM took 1 hour 24 minutes .

Step Time

ImageConversion (virt-v2v) 23 min 26 s

DiskTransfer, about 2.8 MB/s 60 min 42 s

Total 1 h 24 min

At that rate a 500 GiB production disk would take more than two days. Here's why, and the fix.

The symptom

While the copy ran, the migration Pod's log said:

nbdkit: curl[4]: ... virt-v2v monitoring: Progress update, completed 17 %

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nbdkit curl means the disk was being read over HTTPS through vCenter (port 443). That path works anywhere, but it's slow, and it puts the load on vCenter.

The cause

The vSphere provider had no vddkInitImage in its settings:

oc get provider vcenter-lab -n openshift-mtv -o jsonpath = '{.spec.settings}'

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VDDK is VMware's Virtual Disk Development Kit, the same library backup products use.…