Are you running Hyper-V? Have you used up all the available drive letters deploying LUN’s for VM’s in your Failover Cluster? It is fairly easy to get around the 26 drive letter limit in windows when deploying VM’s in a Hyper-V failover cluster configuration. It is possible to deploy 2000 LUN’s to your Hyper-V cluster environment allowing you to grow your cluster and take advantage of your hardware.
In order to grow beyond the 26 drive letters you will need to install HotFix KB951308. Once this hot fix is installed you can create shared storage using the drives GUID rather than drive letter or mount point. Using the drives GUID you can create up to 2000 shared volumes without worrying about running out of identifyers.
