A brief post about something I just learned the hard way: Windows Server 2012 iSCSI Targets do not support dynamically expanding VHDs.
The new iSCSI target that’s integrated into Windows Server 2012 looked like a great tool for setting up a virtual NAS on VMware Workstation to create a SQL Server 2012 failover cluster test environment. FreeNAS 8.3.0, though I am impressed with it, doesn’t work because its iSCSI target (istgt) doesn’t support the required Persistent SCSI-3 reservations.
Microsoft’s iSCSI target supports all the required features for a Windows Failover Cluster. Now my problem is that it doesn’t support using a dynamically expanding VHD as it’s iSCSI Virtual Disk. Any VHD you create using the iSCSI Target in Windows Server 2012 will be a fixed disk. Differencing disks are supported also. I was hoping not to actually have to provision the full 30 GB I was going to pretend SQL Server would have in my test environment (thin provisioning versus thick provisioning). It’s something I would never do in a production environment (for performance reasons, mainly), but to test SQL Server 2012’s clustering setup, it would have been great. So I am going to have to keep looking for alternatives. I think maybe the Starwind iSCSI SAN Free will be my next attempt.