Atomic Test And Set Of Disk Block Returned False For Equality 〈2K — HD〉

Failed creation of new Distributed Virtual Switches (DVS) or PVCs. "Miscompare" warnings appearing in vmkernel.log . Resolution Steps ESXi host HBAs offline - Broadcom support portal

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If the host's Host Bus Adapters (HBAs) have gone completely offline or entered an unrecoverable state, a full host reboot is required to drop the hardware locks and restore path connectivity. Step 3: Analyze the Path and Firmware Compatibility

Reduce the number of VMs or processes accessing a single volume. Excessive metadata updates (like taking many snapshots simultaneously) can overwhelm the atomic locking capacity of the disk. 💡 Summary Table Description Atomic Compare-and-Swap (CAS) Context Filesystem metadata updates / Distributed locking The "False" Result Means the block was modified by another process first Risk Level High (Potential for data inconsistency if ignored) Primary Fix Firmware updates or reducing I/O contention Failed creation of new Distributed Virtual Switches (DVS)

Host log files (such as /var/log/vmkernel.log ) become flooded with SCSI status errors ( H:0x0 D:0x2 P:0x0 Valid sense data: 0xe 0x1d 0x0 ), degrading management plane performance. Step-by-Step Troubleshooting and Resolution

The "false for equality" part means the data currently on the disk is different from the data the host expected to find. Why This Happens

The returned false value for equality may lead to: Step 3: Analyze the Path and Firmware Compatibility

This offloads the test-and-set logic to the storage array itself, which is far more efficient for cluster-wide locking than traditional SCSI reservations that lock entire LUNs.

Understanding the "Atomic Test and Set of Disk Block Returned False for Equality" Error

While the error manifests as a software log entry, it is almost always driven by underlying hardware bottlenecks, misconfigurations, or network instability. Storage Network Latency and Timeout Dropouts or network instability.

If you are seeing this error in your logs, consider these steps from industry guides:

The hostd and vpxa management services on the ESXi host can fall into a degraded state, causing the host to show as "Not Responding" in vCenter.