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Failover Clustering
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Understanding the state of your Cluster Shared Volumes

Rob-Hindman's avatar
Rob-Hindman
Icon for Microsoft rankMicrosoft
Mar 15, 2019
First published on MSDN on Dec 05, 2013 Cluster Shared Volumes (CSV) is the clustered file system for the Microsoft Private cloud, first introduced in Windows Server 2008 R2. In Windows Server 20...
Updated Dec 12, 2024
Version 3.0
cluster shared volumes
cluster troubleshooting
subhasish bhattacharya
windows server 2012 r2
kwester-ebbinghaus-business's avatar
kwester-ebbinghaus-business
Iron Contributor
Jun 23, 2020

Hi Rob-Hindman thanks for your article. 

 

There is a lot of pro and cons of using ReFS as a filesystem for Hyper-V machines. See also 

https://techcommunity.microsoft.com/t5/failover-clustering/cluster-shared-volume-a-systematic-approach-to-finding/bc-p/1483528#M307 + comments

 

Why does a CSVFS preformatted with ReFS prevent DirectIO? - state Server 2019 1809, as of June 2020

The overall other benefits of using ReFS with Hyper-V are clearly documented. Not alone for Storage Spaces Direct. Here we have no Storage Spaces involved at all, but direct attached SAS Frontend LUNs, means storage is directly attached to the cluster nodes.

All CSVFS that are ReFS has Stateinfo FileSystemRedirected, If I create a CSVFS with NTFS 64k, it is going direct. 

 

Example:

CSV-NTFS is a LUN GPT preformatted with NTFS 64k file allocation size
VM-DATA is is a LUN GPT preformatted with ReFS 3.4 (Server 2019) 64k file allocation size

 

 

Nowhere I find a reason for this. Bug? Affects Server 2019. 

 

cc: Elden_Christensen , https://techcommunity.microsoft.com/t5/failover-clustering/cluster-shared-volume-diagnostics/ba-p/371908