MSCS cluster disk going offline in vSAN.

Products

• VMware vSAN

Issue/Introduction

During a planned maintenance event / host reboot MSCS  physical disk resources going into offline or failed state.

From Windows OS level, reports an error as "Cluster physical disk resource terminate encountered an error"

Environment

VMware ESXi 8.x
Microsoft Windows Server Failover Cluster 

 

Cause

The MSCS cluster disk resource went offline because it timed out before the 60-second limit was reached, even though the vSAN iSCSI target failover completed successfully in 56 seconds.

From ESXi, var/run/log/vitd.log "all iSCSI connections are terminated from the Host 'XX' 

2026-03-07T12:22:17.885Z In(14) vitd[2100833]: Thread-0xb9a6c3d500 exiting on signal; reloading empty configuration
2026-03-07T12:22:17.885Z In(14) vitd[2100833]: Thread-0xb9a6c3d500 removing CTL iSCSI ports and terminating all connections.

The initiator' tried to reconnect and was unable to connect to the vSAN iSCSI target Owner host

2026-03-07T12:22:38.173Z In(14) vitd[2100906]: Thread-0x93ba7ad700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): initiator requests to connect to target "iqn.XXXX.XXXX.XXX"; auth-group "#######-e4b0-fe99-####-############"
2026-03-07T12:22:38.174Z In(14) vitd[2100906]: Thread-0x93ba7ad700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): VitdGetTargetAddr: target owner for target iqn.XXXX.XXXX.XXX is 00000000-0000-0000-0000-000000000000
2026-03-07T12:22:38.174Z In(14) vitd[2100906]: Thread-0x93ba7ad700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): Failed to get the owner IPv4 address for target iqn.XXXX.XXXX.XXX, reason: Failure

From vitd.log , event shows that the failover completed in 56 seconds, which is less than the 60-second Windows Disk timeout limit. While the MSCS disk resource should have stayed online, it reported a failure before the timeout was reached.

From ESXi, vitd.logat 12:23:13 UTC, the initiator got connected to the new Owner host for iSCSI target service.
2026-03-07T12:23:13.087Z In(14) vitd[2100906]: Thread-0x93ba7ad700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): initiator requests to connect to target "iqn.XXXX.XXXX.XXX"; auth-group "#######-e4b0-fe99-####-############""
2026-03-07T12:23:13.088Z In(14) vitd[2100906]: Thread-0x93ba7ad700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): VitdGetTargetAddr: target owner for target iqn.XXXX.XXXX.XXX is #####-41bd-bf99-####-############
2026-03-07T12:23:13.088Z In(14) vitd[2100906]: Thread-0x93ba7ad700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): Will redirect connection to target IP/Port: 172.##.#.8:3260
2026-03-07T12:23:13.089Z In(14) vitd[2100968]: Thread-0x31ff30f700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): initiator requests to connect to target "iqn.XXXX.XXXX.XXX"; auth-group "##########-e4b0-fe99-####-############"
2026-03-07T12:23:13.090Z In(14) vitd[2100968]: Thread-0x31ff30f700 172.##.#.70 (iqn.XXX-XX.XX.microsoft:XX.XX.XX): connection handed off to the kernel

Resolution

Engage Microsoft support to investigate why the cluster disk resources transitioned to an offline state