New PVS servers were installed and a new PVS farm created and configured.

• The initial issue in the environment was that imaging wizard would never successfully create a vdisk using option “Create a vDisk”
  • This was worked around by using Imaging Wizard and option “Create an image file” which was then imported into the PVS vdisk store.
• Attempting to boot the UEFI vdisk with a UEFI target device, failed, it would show the boot from vdisk splash message hang for a few minutes and then reboot and repeat.

Checking PVS Server configurations and PVS Server Advanced Properties it was observed that the I/O Burst size was configured to 45 Kbytes, the default size is 32 Kbytes.

Configuring burst size back to default value of 32 Kbytes and restarting the stream service allowed the PVS UEFI target devices to boot successfully and allowed the UEFI master target successfully run imaging wizard using option “Create a vdisk”

The UEFI bootstrap can only use the default value I/O Burst size of 32 Kbytes.

When configured to a higher burst value, the PVS UEFI firmware will not be able to read or write to a streamed vdisk, which will stop imaging tasks from working, and also stop PVS targets booting a vdisk.

General guidance is to use PVS servers with Server Advanced Properties configured to default values for all properties.

PVS Server Advanced Properties -> Network -> I/O Burst Size default is 32 Kbytes. Setting the value higher will stop UEFI target devices booting.