SQL Server FCI CSV storage flips multiple times into Online (No Access) state and eventually fails
Dear Team, I'm encountering an issue with our SQL Server multi‑instance failover cluster after applying the OS security patches and restarting the second node. Once the second node comes back online, the Cluster Shared Volume (CSV) briefly flips multiple times into Online (No Access) state and eventually fails.(we can make it online manually, but again flips and failed after sometime). To make the SQL cluster available, we either need to shut down the VM or revert the patch. Before the patching, all cluster roles and SQL instances were moved off the node, and the cluster appeared healthy. The issue only occurs after the reboot of the second node. (first node patched and restarted and everything working fine) OS : Windows Server 2025 Standard Patch tried: KB5075899 (February,2026 ) KB5078740 (March,2026) KB5082063 (April 2026 ) KB5087539 (May 2026) Could you please advise if there are any specific checks or steps we should follow during OS patching to prevent CSV access loss? Is it an issue with the patch or something else? Any insights or recommended actions would be really helpful to perform the security OS patch in the server Thanks you!
Redundant File Share for SQL Server Failover Instance Installation / Redundant Cluster Shared Volume
Setup : Server 1(S1) Server 2(S2) Domain Controller 1(DC1) Domain Controller 2(DC2) All are Windows Server 2019. S1 and S2 are in a Cluster. I have installed SQL Server Failover Cluster Instance on Server 1 and give a Share of DC1 as the path of root directory of installation. Then add a node(i.e. S2) to the failover cluster instance. Now I want to make the replication of Share of DC1 in DC2, So that if DC1 fails DC2 take care of SQL Instance. Basically I want redundant Cluster Shared Volume. So that if one fails other take care of database/Instance. Please tell me whether it is possible or not. If yes, Then How?
