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This article explains the core components and advantages of Chrony, compares it with ntpd, and provides step‑by‑step configuration and verification commands for deploying Chrony as both NTP client and server on Linux systems.
This article walks through a real‑world OceanBase NTP clock desynchronization problem, demonstrating how the ChatDBA AI assistant guides four rounds of interactive troubleshooting, identifies misconfigured ntpdate‑wrapper scripts, and provides a concrete solution to restore proper time sync.
The International Earth Rotation Service’s decision to skip the 2024 leap second and ultimately abolish leap seconds by 2035 relieves programmers of complex time‑keeping hacks, as current NTP, PTP, and newer Windows systems can already handle adjustments while past leap seconds have repeatedly disrupted software.
With CentOS discontinued, this guide walks through the key considerations and step‑by‑step configurations for DNS, time synchronization, security baselines, SELinux, firewall, and kernel tuning on Ubuntu 22.04 and Anolis 8.6 as viable replacements.
The article analyzes an unusual MySQL replication lag pattern where Seconds_Behind_Master jumps abruptly between 0 and a fixed maximum due to slave clock adjustments, explains the underlying cause, and provides practical steps for time synchronization and IO‑thread handling to resolve the issue.
The article explains why leap seconds are added to keep UTC aligned with Earth's rotation, describes the three time scales (UT1, TAI, UTC), details Linux kernel bugs caused by leap‑second handling across various versions, and offers mitigation scripts while discussing the future removal of leap seconds.
The article analyzes a MySQL MGR cluster failover incident caused by a VM pause and system time jump, explains the underlying detection mechanisms, presents detailed source code excerpts, and demonstrates through debugging that time changes alone do not trigger MGR failover.
The article analyzes the 2012 Azure outage caused by a leap‑year date bug, explains Azure's cluster and Fabric Controller architecture, discusses common leap‑year and leap‑second pitfalls, and shows how time anomalies can cascade through DNS and other cloud services, illustrated with real code examples.
This article explores the origins of time measurement, the transition from astronomical clocks to atomic standards, how UTC and leap seconds are defined, and the technical mechanisms—especially NTP—that keep computers and devices precisely synchronized across the globe.
GPS‑based time synchronization aligns camera, LiDAR, and inertial sensor streams in mapping vehicles by using the satellite‑derived Pulse‑Per‑Second signal and NMEA data to correct the MCU’s clock, handle PPS‑crystal and PPS‑NMEA anomalies, and provide sub‑microsecond timestamps for precise sensor fusion.
This article explains how mismatched server clocks between an email system and a work‑order system can cause workflow approval anomalies, and provides practical steps—including Xshell's broadcast feature—to verify timestamps and prevent such errors in operational environments.
The article explains the historical definition of the second, the concept of leap seconds, their impact on large‑scale IT systems, and details Alibaba's multi‑step approach of splitting the extra second into 86,400 parts to maintain accurate time synchronization across its infrastructure.
The article explains the concept of a leap second, its scheduling by the IERS, the operational impact on large IT systems, and details Alibaba's technical strategy—including testing, time‑distribution methods, and team coordination—to guarantee a seamless transition during the 2015 positive leap second.