Upgrade of VMFS5 locking mechanism from ATS+SCSI to ATS-only does not complete consistently on all ESXi hosts

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Details

After you complete an upgrade of a VMFS5 locking mechanism from ATS+SCSI to ATS-only, the locking mechanism for one of ESXi hosts that share the datastore might still be ATS+SCSI. This inconsistency might cause unpredictable problems and failures, including the following:

• Failures of VMFS datastore rescans
• Failures of lock acquisition for more than 8 hosts
• Failures of lock breaking for more than 8 hosts

Example

When you start to upgrade the VMFS5 locking mechanism to ATS-only on one of the ESXi hosts, other hosts that share the VMFS5 datastore continue using the ATS+SCSI mechanism until the upgrade process is finished on all hosts. In certain circumstances, one of those hosts might experience storage connectivity problems during the upgrade process. In this case, the upgrade to ATS-only proceeds and is reported as successfully completed on all hosts. However, when the problem host regains storage connectivity, the esxcli storage vmfs lockmode list command detects that the host's locking mechanism has not been changed and continues to be ATS+SCSI.

Environment

VMware vSphere ESXi 6.0
VMware vCenter Server 6.0.x

Resolution

Unmount and then remount the datastore on the host.