This article compiles several Zhihu users' candid accounts of a typical Linux operations day, highlighting constant interruptions, emergency firefighting, performance tuning, monitoring, tool development, and a balanced time‑allocation strategy to make ops work more efficient and sustainable.
The article explains JVM runtime memory regions, heap allocation and generational layout, object reference types, major garbage‑collection algorithms and collectors, class‑loading phases, and provides practical tuning commands and case studies for optimizing GC pauses, preventing memory leaks, and diagnosing performance bottlenecks.
This article documents a step‑by‑step investigation of a high TP99 caused by frequent Full GC in a Java service, describing the diagnostic mindset, tools used, GC trigger conditions, object promotion mechanisms, the impact of AdaptiveSizePolicy and Metaspace, and the concrete configuration and code changes that eliminated the issue.
When executing a Spark SQL query with dozens of UNION subqueries that each contain JOIN operations on Spark 3.1.2, the job fails because the total serialized result size of the tasks exceeds the driver’s maxResultSize limit, and the issue can be resolved by reducing the initial partition number used by Adaptive Query Execution.
A new developer refactored a Play‑based API to Spring Boot, encountered severe throughput loss due to implicit suffix path matching, profiled the bottleneck with jvisualvm and wrk, and restored performance by declaring request‑mapping suffixes explicitly, boosting QPS from under 1k to over 9k.
This article walks through a real‑world case of MySQL 5.7 replication delay after switching to TokuDB, presenting a step‑by‑step methodology that examines network, hardware, large transactions, locks, configuration parameters, and multi‑threaded replication to identify and resolve the root cause.
Facing the challenge of storing over 120 billion daily monitoring points from hundreds of thousands of servers, Tencent’s monitoring platform migrated from a custom solution and OpenTSDB to a finely tuned HBase architecture, achieving 3‑5× higher throughput, improved reliability, and significant storage savings.
