Mounting a Volume as a Folder on a Cluster

July 8, 2009 · Posted in SQL Server 

I have recently had an opportunity to learn some new stuff from a customer so I thought I would share. The scenario is implementing an eight instance SQL Server 2008\Windows 2008 cluster with seven drives per instance. If you are sharp, I bet you are saying, “Wait a minute, there are only 20-something drive letters.”. This is true but did you use your toes to count on? ;) You have to use mount points. See below.

image

So let’s continue with one instance of our example. The seven drives would be provisioned something like this:

  • d:\ – 3GB – Program files
  • d:\system – 10GB – System databases and system object filegroup files for every user DB
  • d:\data – 500GB – all user database filegroups files
  • d:\indexes – 300GB – all user index filegroups files
  • d:\bindata – 2TB – all user blob filegroups files
  • d:\TempDBData – 100GB TempDB data files
  • d:\backups – 3TB

Here are the basic steps you go through:

  • Present the LUNs to the OS
  • Create sector aligned partitions
  • Create the root letter formatted with x64 NT allocation units
  • Format the mount points with x64 NT allocation units
  • Create empty folders named accordingly in the root drive. d: in this case
  • Create the mount points just as you would assign a drive letter. See the image above
  • Install your clustered instance to the root drive with system databases going to d:\system in our case.
  • After the installation, make the SQL Service cluster resource dependant on the mount points.(The mounted folders will automatically be added to the cluster group if you install to the root.)

Now before I end, setting it up like this is really dictated by what is important. Unless you just have uddles of disks, this design put aversion to data loss(assuming there are separate disk groups.) ahead of performance. However, that is another conversation.

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Comments

  • Helge Rutz
    Hi Jason,

    I tried the same with W2K8 and SQL 2008 Cluster but ran into trouble with the mount point permission.
    I had to preset the permission on the mounted volume to get the cluster setup succeed. The setup only set the permission on the mount point folder and not on the underlying volume, which cause setup failure with the default permissions.

    Can you explain how you did this in your project?
    I found the permission issue a little bit disappointing.
  • I don't recall having to set permissions but we installed to the root drive and put data\log files on mount point.
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