Many "false for equality" errors stem from firmware bugs in:
Storage arrays handle the hardware execution of the COMPARE AND WRITE command. Bugs in the array's microcode or firmware can cause it to misinterpret the block data, fail to process the atomic transaction fast enough, or falsely report a mismatch. 3. Network Latency and Packet Loss
: In extreme cases, the host may temporarily lose access to the datastore (APD - All Paths Down or PDL - Permanent Device Loss) if the storage queue becomes completely saturated with failed lock retries. Troubleshooting and Resolution Steps
pcs status crm_verify -L -V pcs cluster cib | grep reservation
ATS commands are time-sensitive. If there is high latency, jitter, or dropped packets across the Fibre Channel (FC), iSCSI, or NFSv4.1 storage network, the time window between the host's initial read and its subsequent write wide opens. This increased window elevates the probability of another host altering the data first. 4. Non-Standard Sector Alignment or Replication Many "false for equality" errors stem from firmware
Storage controllers handle ATS commands at the hardware level. Bugs in the array's microcode or firmware can cause the controller to misreport block states, drop ATS commands, or incorrectly process the compare phase. 3. Multipathing and Path Failovers
This error is most frequently seen in the following scenarios:
List all nodes connected to the same LUN:
Most people see this error in the context of . Network Latency and Packet Loss : In extreme
Further reading:
If your host experiences flapping network paths to the storage array (due to a bad fiber channel cable, faulty SFP module, or misconfigured switch), an ATS command may be sent down one path, but the acknowledgment gets lost during a failover. When the host retries over the new path, the state has changed, triggering the error. 4. Non-Standard Sector Formats (Advanced Format Disks)
The error message "atomic test and set of disk block returned false for equality" is a critical VMware ESXi kernel error related to VAAI (vSphere Storage APIs Array Integration)
Checks if the current value equals an expected value. Set: If they are equal, it writes a new value. This increased window elevates the probability of another
: Virtual machines may become unresponsive or report "Invalid" status if the .vmx file lock is lost.
In modern computing, ensuring data integrity across distributed systems or multi-core processors requires these "atomic" operations to prevent race conditions and data corruption. 🛠️ Understanding the Atomic Operation
: ATS is used as a hardware-accelerated locking mechanism to replace traditional SCSI reservations. It allows a host to lock a single block rather than an entire LUN. The Error Meaning