Disabling ATS through CLI

Disabling hardware accelerated locking (ATS) in ESXi

.

An ESXi 5.5 Update 2 or ESXi 6.0 host loses connectivity to a VMFS5 datastore, while using the VAAI ATS heartbeat in your environment. Revert the heartbeat related activity to the legacy method by disabling ATS heartbeat in the ESXi kernel to resolve this issue.A change in the VMFS heartbeat update method was introduced in ESXi 5.5 Update 2, to help optimize the VMFS heartbeat process. Whereas the legacy method involves plain SCSI reads and writes with the VMware ESXi kernel handling validation, the new method offloads the validation step to the storage system. This is similar to other VAAI-related offloads. This optimization results in a significant increase in the volume of ATS commands the ESXi kernel issues to the storage system and resulting increased load on the storage system. Under certain circumstances, VMFS heartbeat using ATS may fail with false ATS miscompare which causes the ESXi kernel to again verify its access to VMFS datastores. This leads to the Lost access to datastore messages ​ Disable ATS heartbeat on ALL hosts under sharing datastore where these errors occur ​To disable ATS heartbeat, run either the CLI command or the PowerCLI command:​

• Command line: # esxcli system settings advanced set -i 0 -o /VMFS3/UseATSForHBOnVMFS5

• PowerCLI: Get-AdvancedSetting -Entity VMHost-Name -Name VMFS3.UseATSForHBOnVMFS5 | Set-AdvancedSetting -Value 0 -Confirm:$false

To enable ATS heartbeat, run either the CLI command or the PowerCLI command:​​

• Command line: # esxcli system settings advanced set -i 1 -o /VMFS3/UseATSForHBOnVMFS5

• PowerCLI: Get-AdvancedSetting -Entity VMHost-Name -Name VMFS3.UseATSForHBOnVMFS5 | Set-AdvancedSetting -Value 1 -Confirm:$false​

To review the results of changing options, run this command:

For example:

# esxcli system settings advanced list -o /VMFS3/UseATSForHBonVMFS5