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Disabling automatic drive letter assignment

Advanced storage configurations in Windows may require you to disable the automatic drive enumeration. Rick Vanover outlines this advanced configuration area of Windows storage.

For certain situations, it may be necessary to tell Windows not to automatically mount new storage that become visible to the server.
This is most frequently used in systems where Microsoft Clustering Services (MSCS) are used, certain virtualization technologies such as VMware Consolidated Backup, or moving a disk from one operating system to another on a shared storage environment.
In the first scenario, MSCS accommodates for this by having Windows not do this by default. The issue is that only Enterprise and Datacenter editions of Windows offer MSCS.
While you can't run MSCS on Standard editions of Windows Server (2003 and 2008), you can enable this auto enumeration of the volumes as they arrive. For Enterprise or Datacenter editions, you can enable this feature by a reverse set of commands from the example.
To do this, you'll need to use the Windows diskpart command to disable automatic drive enumeration on a Windows Standard edition installation with the following commands:
diskpart
automount disable
automount scrub
exit
At this point, the system will automatically mount the drives as they are discovered on the server. This sequence of commands is shown in Figure A.
Figure A

Click the image to enlarge.
This is not a huge change to the storage subsystem, but it is a variant from the default configuration of Windows Server. You should only do this on an as-needed basis and before any shared storage or local storage is attached that isn't backed up yet.
Rick Vanover is a Systems Administrator in Columbus, Ohio. He has more than 12 years of IT experience, and he focuses on virtualization, Windows-based server administration, and system hardware.