Resources disks on a clustered SQL instance


In this post I share with you several recurring questions on managing disks in a cluster failover Windows.

1. Mount points and SQL Server

SQL Server supports mount points if and only if at least one letter named as primary disk for instance. Then you can add your mount points.

SQL Server support for mounted volumes (SQL 2000,2005 and 2008): "SQL Server failover clustered instances fully support mounted drives if the mounted drive is hosted by a cluster drive with a drive letter assigned.Note Because of the number of available drive letters, the number of the virtual instances on a cluster is limited to 25. SQL Server 2005 has the same limitation...."

Known issue:
FIX: You are prompted to format the volume when a formatted volume is mounted on a NTFS folder that is located on a computer that is running Windows Server 2008 or Windows Vista

2. Sharing a disk resource between several group SQL

A resource disk that is already allocated to group SQL can not be reused for another instance in another SQL group.

3. Cluster Shared Volumes (CSV) and SQL Server

CSV is only usable with HyperV for storing virtual machine. It is not so far, an official communication to extend this type of storage to another type of data / configurations.

In Windows Server® 2008 R2, the Cluster Shared Volumes feature included in failover clustering is only supported for use with the Hyper-V server role

4.  Using disks dynamic with cluster

Dynamic disks are not supported natively with Windows 2008 cluster configuration (

However, if you add a third product for managing dynamic disks you can have a support of the editor of the latter.

On the other hand, you will find the following link for information on basic vs. dynamic disks.

Michel Degremont | Microsoft EMEA
Product Support Services Developer - SQL Server Core Engineer |

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