uint32_t stored_crc = read_crc(block); uint32_t computed_crc = crc32(block_data); if (stored_crc != computed_crc) repair_block_from_replica();
If you want, I can produce a short implementation sketch (pseudo-code) for retry + read-after-write verification, or a logging schema for the detailed logs. Which would you prefer?
Are these errors occurring during a like backups or migrations? Share public link
When the disk block reports that the atomic test-and-set has returned false, it is not merely a technical error or a transient state. It is a profound philosophical statement about the nature of reality, time, and the impossibility of true sameness in a dynamic system.
: Used SCSI reservations to lock an entire LUN (Logical Unit Number), preventing other hosts from accessing it entirely during updates. ATS Method
Understanding "Atomic Test-and-Set of Disk Block Returned False for Equality"
Are you experiencing this error during a like a VM power-on, or is it happening randomly across the cluster? Performance issues with VM operations
ATS is a storage hardware acceleration feature (part of VAAI) used by ESXi to lock individual disk blocks rather than an entire LUN.
You may have computed the expected value incorrectly—for example, using a stale version number. Recompute the expected value by re-reading the block immediately before TAS, not relying on cached data more than a few milliseconds old.
grep -i "atomic test and set" /var/log/messages dmesg | grep -i "compare.*write\|reservation" journalctl -xe | grep "false for equality"
[Host VMkernel Log] ScsiDeviceIO: Cmd(0x45d90f0d4e48) 0x89 ... failed H:0x0 D:0x2 P:0x0 Valid sense data: 0xe 0x1d 0x0 DLX: try lock error: Atomic test and set of disk block returned false for equality
Many "false for equality" errors stem from firmware bugs in:
: Attempting to extend an "ATS-only" datastore with a non-ATS LUN, or issues with ATS Heartbeats on certain storage firmware. Troubleshooting & Resolution
Limit the maximum number of concurrent migrations permitted across the cluster network.
user wants a long article about the keyword "atomic test and set of disk block returned false for equality". This phrase appears to be a log message from a database or operating system, likely related to concurrency control, disk block management, or an atomic operation failure. I need to search for this exact phrase and related concepts. I'll break down the search into several categories: exact phrase search, database crash recovery, operating systems, file systems, concurrency control, and possibly specific open-source projects like PostgreSQL or SQLite. I'll also search for "test-and-set" instruction, "atomic" operations, and "disk block" management. search results for the exact phrase have returned some results. The most relevant ones are result 0 from 3parug.com and result 1 from communities.vmware.com. These appear to be forum posts about a VMware ESXi datastore error. The phrase "Atomic test and set of disk block returned false for equality" seems to be a log message from VMware's vmkernel. The search also returned a result about "ATS Miscompare revisited in vSphere 6.5" from cormachogan.com. I should open these pages to get more details. search results provide context for the error message. The user likely wants a comprehensive article explaining this error. I should also search for more technical details about ATS (Atomic Test and Set) in VMware, VAAI, and the SCSI COMPARE AND WRITE command. Additionally, I should look for information on how to troubleshoot this error. search results provide a lot of information. I will now open the most relevant results.
Another host in the cluster might have updated the block or taken the lock while the current host was waiting, leading to a "miscompare".
If a specific storage array struggles to handle ATS cleanly, you can temporarily or permanently disable hardware-assisted locking. For example, in VMware ESXi, you can modify the advanced system settings to turn off ATS and revert to traditional SCSI reservations: VMFS3.HardwareAcceleratedLocking = 0 Use code with caution.
2 thoughts on “Book Blitz ~ Kiss of Darkness by Taylor Aston White ~ Excerpt + Giveaway”
Atomic Test And Set Of Disk Block Returned False For Equality [extra Quality] -
uint32_t stored_crc = read_crc(block); uint32_t computed_crc = crc32(block_data); if (stored_crc != computed_crc) repair_block_from_replica();
If you want, I can produce a short implementation sketch (pseudo-code) for retry + read-after-write verification, or a logging schema for the detailed logs. Which would you prefer?
Are these errors occurring during a like backups or migrations? Share public link
When the disk block reports that the atomic test-and-set has returned false, it is not merely a technical error or a transient state. It is a profound philosophical statement about the nature of reality, time, and the impossibility of true sameness in a dynamic system.
: Used SCSI reservations to lock an entire LUN (Logical Unit Number), preventing other hosts from accessing it entirely during updates. ATS Method Share public link When the disk block reports
Understanding "Atomic Test-and-Set of Disk Block Returned False for Equality"
Are you experiencing this error during a like a VM power-on, or is it happening randomly across the cluster? Performance issues with VM operations
ATS is a storage hardware acceleration feature (part of VAAI) used by ESXi to lock individual disk blocks rather than an entire LUN.
You may have computed the expected value incorrectly—for example, using a stale version number. Recompute the expected value by re-reading the block immediately before TAS, not relying on cached data more than a few milliseconds old. ATS Method Understanding "Atomic Test-and-Set of Disk Block
grep -i "atomic test and set" /var/log/messages dmesg | grep -i "compare.*write\|reservation" journalctl -xe | grep "false for equality"
[Host VMkernel Log] ScsiDeviceIO: Cmd(0x45d90f0d4e48) 0x89 ... failed H:0x0 D:0x2 P:0x0 Valid sense data: 0xe 0x1d 0x0 DLX: try lock error: Atomic test and set of disk block returned false for equality
Many "false for equality" errors stem from firmware bugs in:
: Attempting to extend an "ATS-only" datastore with a non-ATS LUN, or issues with ATS Heartbeats on certain storage firmware. Troubleshooting & Resolution in VMware ESXi
Limit the maximum number of concurrent migrations permitted across the cluster network.
user wants a long article about the keyword "atomic test and set of disk block returned false for equality". This phrase appears to be a log message from a database or operating system, likely related to concurrency control, disk block management, or an atomic operation failure. I need to search for this exact phrase and related concepts. I'll break down the search into several categories: exact phrase search, database crash recovery, operating systems, file systems, concurrency control, and possibly specific open-source projects like PostgreSQL or SQLite. I'll also search for "test-and-set" instruction, "atomic" operations, and "disk block" management. search results for the exact phrase have returned some results. The most relevant ones are result 0 from 3parug.com and result 1 from communities.vmware.com. These appear to be forum posts about a VMware ESXi datastore error. The phrase "Atomic test and set of disk block returned false for equality" seems to be a log message from VMware's vmkernel. The search also returned a result about "ATS Miscompare revisited in vSphere 6.5" from cormachogan.com. I should open these pages to get more details. search results provide context for the error message. The user likely wants a comprehensive article explaining this error. I should also search for more technical details about ATS (Atomic Test and Set) in VMware, VAAI, and the SCSI COMPARE AND WRITE command. Additionally, I should look for information on how to troubleshoot this error. search results provide a lot of information. I will now open the most relevant results.
Another host in the cluster might have updated the block or taken the lock while the current host was waiting, leading to a "miscompare".
If a specific storage array struggles to handle ATS cleanly, you can temporarily or permanently disable hardware-assisted locking. For example, in VMware ESXi, you can modify the advanced system settings to turn off ATS and revert to traditional SCSI reservations: VMFS3.HardwareAcceleratedLocking = 0 Use code with caution.
It does, doesn’t it? You’re welcome! I hope you enjoy it when you read it! Thanks for commenting!