Atomic Test And Set - Of Disk Block Returned False For Equality //free\\

窶弋he atomic test-and-set operation on the disk block returned false when checking for equality, indicating that the current value in the block did match the expected value. This suggests a concurrent modification or a stale expected value 窶� the operation failed as designed, preventing a potential race condition or lost update.窶�

: The host often loses access to the datastore, causing virtual machines to hang, crash, or enter a "grayed out" state. Common Triggers Storage Latency 窶弋he atomic test-and-set operation on the disk block

10-node Ceph cluster, BlueStore backend, NVMe-over-Fabrics. Error: OSD logs repeated: bluestore/StupidAllocator.cc: atomic test and set of disk block 0x4a20b returned false for equality . Root cause: A network partition caused two OSDs to believe they held the same allocation bitmap lock. The storage array (NVMe target) correctly rejected the second OSD窶冱 compare-and-write. Fix: Reduced osd_heartbeat_grace from 20s to 5s, enabled faster fencing, and implemented retry logic with jitter. Error: OSD logs repeated: bluestore/StupidAllocator

TAS is a non-blocking operation. If it returns false , the correct response is often to re-read the block, update your expected value, and retry. For example: Fix: Reduced osd_heartbeat_grace from 20s to 5s, enabled

Are you seeing this error in a , or is it appearing during a specific operation like mounting a datastore ?

If you've spotted this in your VMkernel logs, you aren't just looking at a minor storage hiccup. You've encountered an ATS Miscompare