Atomic Test And Set Of Disk Block Returned False For Equality Official

Why would the equality test fail? Usually, it's one of three scenarios: 1. "Split Brain" or Multi-Host Contention

Look for spikes in command latency. ATS is very sensitive to timing; if the storage is overloaded, ATS failures will increase.

Use command-line tools (like esxcli storage core device vaai status get ) to ensure the array is actually reporting ATS as "supported." Conclusion Why would the equality test fail

Ensure your HBA (Host Bus Adapter) drivers and the storage array firmware are on the vendor's "Compatibility Matrix."

Understanding the "Atomic Test-and-Set of Disk Block Returned False for Equality" Error ATS is very sensitive to timing; if the

If the host cannot "set" the lock, it cannot write to the disk.

If it matches (equality), the host updates the block with its own signature to claim ownership. In some specific storage environments (notably certain older

In some specific storage environments (notably certain older NAS or SAN setups), the ATS heartbeating mechanism is too aggressive. VMware allows you to revert to traditional SCSI reservations for heartbeating while keeping ATS for other tasks, though this should only be done under the guidance of support.