Mount Points and Clustering blurb for SQL Server & windows operating system

Mount Point is the new concept introduced in the Windows 2003 Server (R2) that  works as a mounted drive is a volume or a drive that is mapped to a folder on a volume that uses the NTFS file system.  Mounted drives function as any other volume or drive.  A mounted drive is assigned a drive path instead of a drive letter. In SQL Server 2005 the root shared disk needs a drive letter.  You can create any number of mount points to this root drive.  The mount point drives need not have a drive letter.  In other words, you should be able to access your mount point drives with reference to a drive letter.

For me having experience in the UNIX world mount points are important in SQL Server to bring up here because one of the many purposes for having mount points is to do away with the limitation of A-Z drive lettering.  That intention is achieved for SQL on Windows 2003 when it comes to standalone installations.

How about working within Clustering Environment?

Still there are few limitation with regard to MSCS service in Windows 2000 & 2003 versions due to the hardware & firmware processes. Due to the configuration the failover process does not handle mount points without a one-for-one mapping to a shared disk, then the A-Z drive lettering restriction is still present. A betterment in SQL 2005 for any cluster group is you may have many shared disks (mount points) which only need one drive name.

KBA  on configuring the mount points on MSCS

In case if you are upgrading the SQL Server 2000 Clustering environment to SQL Server 2005, then you could take help of mount points to handle multiple instance that clears up physical space for Server consolidation purpose. As mentioned you could use mount points in SQL Server 2005, but this is not supported in SQL Server 2000 version even though if you have Windows 2003 R2 operating system.