TCP

Why Tune the Linux Network Stack The Linux kernel’s default network parameters are designed for general-purpose scenarios — conservative and safe. However, under high-concurrency web services, large-scale load balancers, CDN nodes, and similar workloads, these defaults become bottlenecks. Typical symptoms include: dmesg showing nf_conntrack: table full, dropping packet ss -s showing a large number of TIME-WAIT connections During load testing, CPU is not saturated but throughput plateaus NIC PPS (packets per second) is far below hardware capability Most of these issues stem from untuned kernel network parameters....

Overview The Linux kernel exposes thousands of tunable parameters through /proc/sys/ and the sysctl interface, covering networking, memory, filesystem, security, and more. Properly adjusting these parameters can significantly improve system performance and stability, but blind tuning can be counterproductive. This article systematically covers the sysctl system across four dimensions — networking, file descriptors, memory, and security — and provides production tuning templates and parameter validation methods. sysctl System Viewing and Modifying Parameters # View all parameters $ sysctl -a # View specific parameter $ sysctl net....