iSCSI Target in Windows Server 2012 R2 *does* support dynamically expanding VHDX

As an update to a previous post (, Windows Server 2012 R2 now supports mapping iSCSI targets to dynamically expanding VHDX.

It comes with a major catch though: you cannot create, for example, a 2 TB iSCSI target on a 60 GB disk. You can however create two 60 GB targets on a single 60 GB disk. In other words, each target cannot have a maximum size larger than the size of the disk. If you attempt to create a larger iSCSI target, you’ll get this friendly error message:

Server 2012 R2 iSCSI Wizard
Error message when trying to create a 2 TB iSCSI target on a volume with only 0.05 TB free space.

For production environments, this feature is probably of little use anyway. However, for test or staging environments where space may be at a premium but you want to test automation or a script, this could have been very handy. And of course, it would be very handy for speakers who want to build demo environments with realistic numbers without needing an actual multi-terabyte storage array in your trunk.

There is a bigger picture consideration. For me, this was the first time I’d created an iSCSI target on Windows Server 2012 R2. It’s not been available that long and I have one Hyper-V host running in production but there it is not an iSCSI target host. With more frequent releases of Windows Server, Microsoft will be adding value to the operating system in small increments. The increased release cadence may lead to more Windows versions being skipped – especially on the server OS. As IT professionals, we should however keep up with each release and its new and enhanced features because otherwise the leap after 3-4 years may be much larger than we anticipate.

Have you deployed “12R2” in your lab? Have you experimented with the new features such as Work Folders or Hyper-V Replica to a third server? What do you do to keep your lab and skills current?

Let me know what you think, or ask a question...

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