The Failover Cluster Validation Wizard can perform a number of storage tests to determine the suitability and supportability of the shared storage of a potential new cluster. This is important for a Hyper-V cluster that will use directly attached shared storage such as a SAN (not SMB 3.0).
Microsoft has published a KB article for when these storage tests on a multi-site (stretch, cross-campus, or metro) failover cluster may not discover all shared LUNs on Windows Server 2012 or Windows Server 2012 R2.
Symptoms
Consider the following scenario:
- You have a Windows Server 2012 or Windows Server 2012 R2 multi-site failover cluster.
- A multi-site storage area network (SAN) is configured to have site-to-site mirroring.
- You use the Validate a Configuration Wizard to run a set of validation tests on the failover cluster.
In this scenario, storage tests may not detect all logical unit numbers (LUNs) as shared LUNs.
Cause
Storage validation test selects only shared LUNs. A LUN is determined to be shared if its disk signatures, device identification number (page 0×83), and storage array serial number are the same on all cluster nodes. When you have site-to-site mirroring configured, a LUN in one site (site A) has a mirrored LUN in another site (site B). These LUNs have the same disk signatures and device identification number (page 0×83), but the storage array serial number are different. Therefore, they are not recognized as shared LUNs.
Resolution
To resolve the issue, run all the cluster validation tests before you configure the site-to-site LUN mirroring.
Note If the validation test is needed afterward for support situations, LUNs that are not selected for storage validation tests are supported by Microsoft and the storage vendor as valid Shared LUNs.