Any registry settings to override the restriction of using DFS enabled network share for quorum disk config?

Question

Hi,

This is Hemanth from Nutanix. Recently, we have come across an enforcement on using the DFS enable network file server share as a quorum disk for failover cluster config.

https://learn.microsoft.com/en-us/windows-server/failover-clustering/file-share-witness [nam06.safelinks.protection.outlook.com]

In “Other notes” section:

The use of a Distributed File System (DFS) share or replicated storage is not supported with any version of failover clustering. These can cause a split brain situation where clustered servers are running independently of each other and could cause data loss.

Would like to know if we have any registry settings to disable this restriction on windows server versions 2019 and 2022.

Thanks,
Hemanth.

Answer 1

Hello there,

It is not advised to do so. Domain-based namespaces do not support the use of failover clusters as namespace servers.

One of the quorum models for Failover Clustering is the ability to use a file share as a witness resource. As a recap, the File Share Witness is designated a vote in the Cluster when needed and can act as a tie breaker in case there is ever a split between nodes (mainly seen in multi-site scenarios).

However, over the years, we have seen where this share is put on a DFS Share. This is an awfully bad idea and one not supported by Microsoft.

More info here https://techcommunity.microsoft.com/t5/failover-clustering/failover-cluster-file-share-witness-and-dfs/ba-p/372147

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Answer 2

Understood the reason. But this enforcement is getting applied for any file server share(esp non-MS) which advertise DFS capability. For ex, Nutanix Files uses DFS for scale out share. Doesn't really cause the split-brain situation anytime.

We would like to know if there is any registry setting to override this enforcement assuming that admins are using non-MS DFS enabled shares.