I have seen the CSV redirected access error messages in the Hyper-V cluster event log many times. It only happens after the business hours and only lasts for a few minutes every time.
Cluster Shared Volume ‘Volume3’ is no longer directly accessible from this cluster node. I/O access will be redirected to the storage device over the network through the node that owns the volume. This may result in degraded performance. If redirected access is turned on for this volume, please turn it off. If redirected access is turned off, please troubleshoot this node’s connectivity to the storage device and I/O will resume to a healthy state once connectivity to the storage device is reestablished.
After spending some time to dig deep into this issue in the past two days, I can confirm this issue was caused by the Backup Exec. The error message generally starts to show 2~3 minutes before the backup job of Hyper-V virtual machines on the cluster shared volume starts, and ends 2~3 minutes after the Hyper-V virtual machine backup job finished. After suspend that backup job, there are no more such issues.
To avoid this, a good practice is – do NOT run the backup job against the same CSV at the same time.