If the host cannot "set" the lock, it cannot write to the disk.
To detect corruption before test-and-set: If the host cannot "set" the lock, it
: Check for known ATS-related bugs in your storage array's firmware version, as some vendors have specific patches for "false ATS miscompares". ESXi host HBAs offline - Broadcom support portal A power failure or firmware bug causes a
If they match ( equality ), the host immediately writes new data to the block in one atomic operation . The return of false for equality during an
A power failure or firmware bug causes a block to be half-updated (torn write). Result: The compare phase sees a corrupted value → equality fails. Solution: Enable end-to-end data protection (T10 DIF/DIX), use checksums, and rely on battery-backed RAID cache.
The return of false for equality during an atomic test and set operation on a disk block suggests that:
This occurs during an operation, a hardware-accelerated locking primitive where a host attempts to claim or update metadata on a shared storage array. When the "test" (checking if the block's current value matches what the host expects) fails—returning false for equality —it means another host likely changed that block since it was last read, causing a miscompare . Feature Overview: VAAI Atomic Test and Set (ATS)