In order to do anything involving a SQL Server clustered instance (restore, backup, store/read data) storage must be accessible to the clustered instance. Here we will discuss the process of how to add a new LUN to a SQL cluster.
First off, have your storage admin add the disk, and make it accessible to all of the nodes of the cluster. Most SANs are different, so I’m not going to discuss that syntax here.
The next step is a little painful, you need to go to each of your cluster nodes and do a rescan of storage. In order to do this, go to Server Manager and right click on Disk Management > Rescan Disks
Next, go the server where the cluster service you would like to add the disk to is running (you can accomplish this by entering the virtual cluster name into Terminal Services) and online the disk (From Disk Management)
After the disk is brought online, it must be initialized. This is done from the same disk management dialogue. Configure this with either a MBR or GUID partition table (preferable for very large LUNS).
Next create the volume, in order to this, right click in the disk area, and select “New Simple Volume”
To create this drive under an existing drive letter (which I like to do for clustering) select “Mount in the following empty NTFS folder”
Create a new folder under the drive letter associated with your cluster resource group. I typically name the folder $RESOURCE_GROUP_$PURPOSE. Where resource group would RG1_ and purpose would be backup/data/logs.
Lastly, you need to label your volume and format. Once again for clarity, I usually for $RESOURCE_GROUP_Identifier_$PURPOSE_$LUN#.
Next, launch failover cluster manager (this can run either on your server or desktop). Select manage a cluster, and the enter the name of the cluster you are managing (if it doesn’t auto-populate)
Right click on the Storage folder on the right and select add a disk. If the disk is presented and configured properly, the cluster should see it, and add it to available disks.
Expand the left hand window and select “Services and Applications”
Right click on the instance you would like to add the storage to, and select “Add Storage”. A dialogue box will pop up with the available disks to add.
This is where you select the appropriate disk and add it into your cluster. You should be able to identify by its disk number and volume information.
Go into SSMS and using the Attach Database dialogue (or any dialogue that interacts with the files system–backup/restore, etc), and verify that SQL Server can see the disk.