Disklibrary on Windows 2025 Cluster Shared Volumes incompatible with 11.40 ?

Question

Hi,I’m using Microsoft CSVs for quite some time now, to setup shared libraries on block storage.My current setup on Windows 2025 (24H2) is now reporting an incompatible filter driver in the filesystem stack.Up to Windows 2022, I do not see this behaviour.The incompatible driver, leads to indirect I/Os against the Filesystems, which leads to a degradation in throughput and increase in CPU and network utilization on the MediaAgents.Is there an update available, fixing this in CV11.40 ?I’m currently using MR56 in the environment and deactivated the Ransomware Protection on the MediaAgents to avoid this.Once activated, the CVDLP filter driver gets active again and the ClusterVolumeState changes from direct to indirect due to incompatible filter driver.I faced a similar issue some 10 years ago with Version 11.6 of Commvault and Microsoft 2012R2, where this has been solved by Commvault with a patch/FixBRKlaus

Mohammed Ramadan · Accepted Answer

HiKlaus ,Good day ,we have a KB article for this issue. Have you had a chance to review it?Hyper-V Cluster CSV Performance Degradation due to CVDLP Filter Driver on Windows Server 2025to resolve this issue add the CVDLP driver to theSharedVolumeCompatibleFiltersregistry key on all nodes in the cluster.Thanks ,Ramadan