This guide explains NUMA memory hierarchy, shows how to install and use the numactl command, interprets hardware and NUMA statistics, and presents memory allocation strategies to improve performance on multi‑node Linux systems.
The Linux community announced the first release candidate of the 5.14 kernel, featuring contributions from about 1,650 developers, over 13,000 commits, new memfd_secret system call, extensive driver and architecture updates, and numerous core subsystem enhancements.
This guide explains why large files often need to be split on Linux for network transfer, demonstrates how to use the split command with various options and examples, and shows how to recombine the pieces efficiently using the cat command.
This article explores the IPVS kernel load‑balancing mechanisms, detailing ten built‑in connection scheduling algorithms, introducing a dynamic‑feedback load‑balancing strategy that adjusts server weights based on real‑time metrics, and explains how to compute aggregate load and weight adjustments to achieve optimal scalability and transparency.
This guide explains how to install the Go‑based Ascii Image Converter on Linux, use it to transform JPEG, PNG, BMP, WEBP, or TIFF files (or URLs) into monochrome or colored ASCII art, and customize output size, character sets, and saving options.
This guide explains the NFS (Network File System) protocol, its reliance on RPC, the ports it uses, how to activate the required daemons, differences among NFSv2/v3/v4/v4.1, and provides step‑by‑step instructions for installing, configuring, and mounting NFS on CentOS 7, including firewall and export settings.
This article introduces systemd as the modern Linux init replacement, explains its key features and unit file syntax, and provides three hands‑on examples showing how to manage nginx, Tomcat, and a custom JAR service with systemd commands and configuration files.
This article outlines practical shell‑script guidelines for automating system and application operations, covering script header conventions, formatting, error handling, safe use of commands, variable handling, file packaging, pipeline restrictions, concurrency locks, logging, and risk‑mitigation strategies to make automation both efficient and secure.
This article explains the inner workings of the Linux netstat command, walks through reading /proc/net/tcp and related files, demonstrates how to map sockets to processes, and provides a complete Go implementation of a lightweight netstat utility with code examples and detailed parsing logic.
This article provides a comprehensive introduction to Docker, explaining how Linux containers isolate processes, how Docker packages applications and dependencies into portable images, and why Docker simplifies environment management, version control, sharing, and deployment for modern cloud‑native workflows.
This comprehensive guide explains the architecture and working principles of Linux Virtual Server (LVS), details its NAT, DR, TUN, and FULLNAT modes, explores session persistence techniques, reviews ten scheduling algorithms, and compares LVS with Nginx for high‑performance load balancing.
Learn six effective ways to execute Linux commands in the background—including using &, bg, nohup, output redirection, disown, and tmux—so you can keep working in the same terminal or close it without stopping long‑running tasks.
This article dives deep into the Linux kernel implementation of the listen system call, explaining how the kernel creates and initializes the full‑connection and half‑connection queues, how backlog and system parameters interact, and why these steps are essential before a server can accept client connections.
The article introduces the command‑line utility q, explains how to install it on Linux and Windows, and demonstrates using familiar SQLite‑style SQL queries to search, filter, join, and aggregate log files and command output, offering a convenient alternative to traditional shell tools.
This article explores why a server must call listen() before accept() by dissecting the Linux kernel's listen system call, its interaction with socket objects, and how the kernel calculates and initializes the full and half‑connection queues based on backlog and system parameters.
This article explains why binding a process to a specific CPU improves cache performance, shows how to set CPU affinity on Linux using the sched_setaffinity system call, and walks through the kernel's internal implementation—including run‑queue structures, migrate_task, and __migrate_task—illustrated with code and diagrams.
This article explains the purpose of the TCP TIME-WAIT state, the scenarios it protects against, common misconceptions, and practical Linux kernel tweaks—such as fast recycle, socket reuse, and tw_buckets settings—to manage TIME-WAIT efficiently on high‑concurrency servers.
This article provides a comprehensive introduction to the fundamentals of x86 Linux, covering the historic Intel 8086 processor, segment descriptors, main memory organization, registers, bus architecture, CPU addressing modes, control mechanisms, and the basic instruction execution cycle.
This article introduces Linux cluster fundamentals, explains key concepts such as scalability, high availability, load balancing, and error recovery, categorizes clusters into high‑availability, load‑balancing, and high‑performance types, and outlines common architectures, technologies, and implementation methods for building robust, fault‑tolerant systems.
This guide explains why database backups are essential, walks through creating a backup directory, writing a mysqldump shell script, compressing the dump, granting execution rights, and scheduling the script with cron to run every minute.
This comprehensive tutorial walks through preparing the environment, configuring yum repositories and hosts, installing Oracle Grid Infrastructure with ASM disk groups, creating ASM disks, and finally building an Oracle database on a CentOS 7 system, including command examples and GUI steps.
This tutorial explains what Nushell is, lists the required development packages, and provides detailed commands to download, extract, and install the latest Nushell binaries and plugins on Ubuntu/Debian, RHEL‑based Linux, macOS, and Fedora, plus how to set it as the default shell for a new user.
This article explains why Linux uses virtual IRQ numbers, describes the irq_domain framework and its data structures, compares linear, tree, and no‑mapping strategies, and walks through the complete interrupt‑mapping process on an ARM64 platform with code examples.
This article provides a practical guide to tuning Linux kernel parameters and NGINX configuration directives—such as backlog queues, file descriptors, worker processes, keepalive connections, access‑log buffering, sendfile, limits, caching and compression—to achieve optimal web server performance for high‑traffic sites.
This article explains what Linux load average actually measures, distinguishes it from CPU utilization, describes runnable and uninterruptible states, and demonstrates its behavior through CPU‑intensive, I/O‑intensive, and high‑process‑count scenarios using common monitoring tools.
This guide explains how to install the ngx_http_geoip2 module, upgrade Nginx, configure GeoIP2 databases, and modify the Nginx configuration to block requests from foreign IP addresses, providing step‑by‑step commands and example code for a Linux server.
This comprehensive tutorial explains DNS fundamentals, common record types, essential command‑line tools, BIND installation, zone file creation, master‑slave replication, reverse zones, sub‑domain delegation, forwarding, view‑based responses, and compiling BIND from source, providing a full roadmap for setting up reliable DNS services on Linux.
This guide walks through a collection of frequently used Linux shell commands—grep, custom alias shortcuts, pwd, find, history, od, and for loops—explaining their common scenarios, key options, example usages, and handy tricks to boost productivity in everyday development and scripting tasks.
Learn how to use the Linux ulimit command to inspect and modify both hard and soft resource limits, understand the meaning of limit values such as hard, soft, and unlimited, and apply temporary or permanent changes via command line or the limits.conf file.
Understanding Linux load average and CPU utilization, this guide explains process states, how load is calculated, the difference between load and CPU usage, common bottlenecks, and step‑by‑step troubleshooting techniques using tools like top, vmstat, pidstat, iostat, and perf.
The article explains why Linux newcomers should embrace the command‑line interface, highlighting benefits such as easier troubleshooting, remote SSH access, richer toolsets, essential server management, structured syntax, and shortcuts, while also showing how to open a terminal and start using it effectively.
This guide presents 27 practical Linux command-line techniques—from safe file deletion and alias management to process monitoring, log handling, and advanced shell shortcuts—designed to help heavy users work more efficiently and avoid common pitfalls.
A recent GitHub disclosure reveals that a long‑standing polkit vulnerability (CVE‑2021‑3560) enables unprivileged local users on many Linux distributions to obtain root privileges with just a few commands, prompting urgent updates for affected systems such as RHEL, Fedora, Debian and Ubuntu.
This guide explains why Nacos generates massive access logs, shows how to disable the Tomcat access log via configuration, provides a cron script for log cleanup, demonstrates dynamic log‑level adjustment through API calls, and details fine‑grained logback settings for better log management.
This article explains core Linux I/O concepts—including file systems, I/O types, caching mechanisms, copy‑on‑write, zero‑copy, and performance metrics—then presents practical application, file‑system, and disk‑level optimization techniques to improve throughput and latency.
This tutorial walks through installing Docker CE on CentOS, then pulling and running Elasticsearch and Kibana containers, configuring Kibana, and setting up the Cerebro monitoring tool, providing all necessary commands and configuration snippets for a complete ELK stack deployment.
Learn how to create temporary and permanent Linux aliases to replace lengthy commands, streamline file synchronization with rsync, manage aliases via the alias and unalias commands, and store them in dedicated files for persistent shell customization.
This article explains Kubernetes' deprecation of Docker, introduces containerd as a lightweight, industry‑standard runtime, and provides step‑by‑step instructions for installing, configuring, and operating containerd on Linux, including common CLI commands for managing images and containers.
This comprehensive guide walks you through Docker fundamentals, compares virtual machines to containers, explains core concepts, shows step‑by‑step installation, image building, container execution, and best practices, enabling you to containerize a Vue project and deploy it with Nginx effortlessly.
This article explains the differences between epoll's level‑triggered (LT) and edge‑triggered (ET) modes, shows how to use epoll_create, epoll_ctl, and epoll_wait, provides complete C++ examples for read and write handling, and offers practical guidance on avoiding common pitfalls in high‑performance Linux network programming.
Learn how to install and configure Samba on Linux, covering the service’s history, required packages, daemon processes, main configuration file settings, command‑line tools, SELinux integration, and step‑by‑step client and server setup for Windows and Linux file sharing.
This guide explains how to install the uptimed daemon on various Linux distributions, enable and start its service, and use the uprecords command with its many options to view detailed system uptime, boot, and downtime histories.
This article introduces the command‑line utility q, explains how to install it on Linux and Windows, and demonstrates using full SQLite‑compatible SQL syntax to query, filter, join, and aggregate plain‑text log files, offering a database‑style alternative to traditional shell tools.
This article provides a comprehensive, hands‑on guide to building a MySQL master‑slave cluster with GTID replication and configuring MHA for automatic failover, covering environment preparation, password‑less SSH, MySQL settings, MHA installation, custom scripts, testing, and the key advantages of the solution.
This article explains the object‑oriented design of the Linux VFS, details the four core VFS structures, shows how ext4 is registered and mounted via register_filesystem and ext4_mount, and walks through the six‑step ext4_fill_super process for initializing superblocks and related metadata.
A comprehensive, categorized list of essential Linux commands covering system information, file management, process control, networking, package handling, disk operations, backups, and text editing, providing quick reference examples and usage syntax for everyday system administration tasks.
This article provides a comprehensive reference of Linux commands, explaining their purpose and usage across categories such as file management, system monitoring, networking, user administration, and process control, helping readers efficiently manage and troubleshoot Linux systems.
This guide explains the NFS protocol fundamentals, activation steps, version comparisons, and provides a step‑by‑step CentOS 7 installation and configuration tutorial, including service setup, firewall adjustments, export file editing, and client mounting procedures.
Learn step-by-step how to create a reliable MySQL database backup solution by writing a shell script, compressing the dump, assigning execution permissions, and scheduling it with cron to run automatically, while covering storage media choices, disk space checks, and verification of the backup process.
This article explains the four core parts of a Linux system—kernel, shell, filesystem and applications—covering memory and process management, VFS architecture, file types, directory hierarchy, partitioning, mounting, links and essential command‑line tools.
This article explains the core concepts of Linux virtual memory, including why it exists, how paging and page tables work, the role of the MMU, swap usage, common pitfalls, and practical commands for inspecting and tuning memory behavior on a Linux system.
This tutorial explains how to download a CentOS 7 Docker image, run it as a lightweight Linux virtual machine, map ports and directories, access the container's shell, and export or import the container as an image for easy migration across hosts.
This guide walks through installing rsync on CentOS and demonstrates nine real‑world examples—including local directory sync, preserving timestamps, remote transfers, avoiding overwrites, progress monitoring, deletion, include/exclude patterns, and size limits—complete with commands, output, and key options.
This article explains why the ELK stack is useful for large‑scale log collection and analysis, then provides detailed installation, configuration, and integration steps for Elasticsearch, Logstash, and Kibana on both macOS and Linux, including common pitfalls and memory‑tuning tips.
On Linux, the client port used in a TCP connection is selected either by the kernel during the connect system call—randomly scanning the ip_local_port_range while respecting reserved ports—or by a prior bind call, with detailed kernel functions such as inet_hash_connect and __inet_hash_connect governing the process.
This article compiles a comprehensive list of open‑source Linux applications, covering audio players, chat clients, backup and recovery utilities, desktop customization themes, development IDEs, e‑book managers, editors, educational software, email clients, file managers, games, graphics tools, browsers, office suites, productivity helpers, security utilities, file‑sharing services, terminal emulators, miscellaneous utilities, video players, and other useful programs.
Learn how Linux selects the next process for CPU execution by exploring key scheduler structures such as task_struct, sched_class, runqueue, the various scheduling policies (CFS, RT, Deadline, etc.), the scheduling flow, and the low‑level context_switch mechanism that swaps address spaces and registers.
This article explains the difference between CPU utilization and CPU load, describes how to interpret these metrics, and provides practical Linux commands and step‑by‑step methods for diagnosing high load with low utilization or vice versa, including common I/O and indexing issues.
The article explains how MySQL uses different memory areas such as Thread Memory, Sharing, and InnoDB Buffer Pool, describes the impact of large user tables on query performance, and shows that when a table size exceeds the InnoDB buffer pool capacity, sharding becomes necessary.
This tutorial walks through building a three‑node UCloud lab, installing ipvsadm, configuring NAT and TUNNEL load‑balancing modes with LVS, adjusting routing and ARP settings, and verifying the setup using ipvsadm commands and curl requests.
This guide walks through upgrading GCC, extracting and installing Redis 6.2.4 on a Linux server, configuring a systemd service, verifying the installation, and provides basic performance tuning tips such as adjusting max connections, memory settings, data compression, and clustering.
Learn how Linux’s non‑blocking I/O mechanisms such as select, poll, and epoll enable high‑concurrency servers, explore OpenResty’s Lua‑based architecture, and follow step‑by‑step instructions for installing, configuring, and troubleshooting a performant OpenResty/Nginx environment on Linux.
This guide provides a comprehensive overview of the FTP protocol and its lightweight counterpart TFTP, then walks through installing, configuring, and securing the vsftpd service on Linux, covering active and passive modes, authentication options—including anonymous, local, and virtual users via text files or MySQL—and essential SELinux and firewall adjustments.
This guide explains why large files often need to be divided for network transfer on Linux, and provides step‑by‑step commands and options for using the split utility to cut files into smaller pieces and the cat command to recombine them efficiently.
The article walks through Linux’s mmap file‑read workflow—from the kernel entry point and VMA creation, through page‑fault handling that allocates pages and invokes synchronous or asynchronous readahead, to munmap’s unmapping steps and the deferred file‑cache reclamation mechanisms.
This tutorial walks you through why ELK is essential for large‑scale log collection, shows a simple architecture diagram, and provides detailed installation and configuration steps for Elasticsearch, Logstash, and Kibana on both macOS and Linux, including common pitfalls and Java integration.
This step‑by‑step tutorial shows how to enable security groups, configure firewall ports, install the BT panel or use the command line to set up a Linux server, then install JDK, Tomcat, and Docker CE with all required commands and configurations.
This article explains how Docker volumes work, how to mount host directories into containers using the -v and --mount options, and demonstrates data persistence by creating a volume, inspecting its storage location, and verifying that files created inside the container appear on the host.
An intermittent 403 error caused by nginx reuseport misrouting on a shared IP was traced to kernel listener hash table ordering; upgrading the Linux kernel from 4.14 to 4.16+ resolved the issue by prioritizing IP+PORT over INADDR_ANY lookups.
This guide explains time‑zone fundamentals, compares ntpd and ntpdate, and provides step‑by‑step commands to install, configure, secure, and verify NTP services on Linux, ensuring reliable and precise system time across servers.
Linux users often need more than a single terminal window, so this guide compares four popular terminal multiplexers—tmux, GNU Screen, Konsole, and Terminator—evaluating their splitting, stacking, control keys, package size, and hacker-friendly features to help you choose the best tool for your workflow.
This guide shows Linux users how to retrieve detailed CPU information—including model, frequency, physical and logical core counts, and hyper‑threading status—by querying /proc/cpuinfo with simple command‑line filters.
This article explains the fundamentals of virtual memory in Linux, covering its purpose, paging and page tables, address translation, swap usage, common questions about 32‑ vs 64‑bit systems, direct memory access, JVM memory consumption, and essential commands for monitoring and configuring memory.
This article explains what Docker is, its underlying architecture—including namespaces, cgroups, and union file systems—its client‑server model, its core concepts such as images and containers, its installation methods, a step‑by‑step Koa hello‑world example, and how to migrate containers using export and import commands.
This comprehensive tutorial explains what tcpdump is, how it differs from Wireshark, walks through its core parameters, output format, common and advanced filtering rules, optional flags, and provides dozens of practical command‑line examples for precise packet capture on Unix systems.
This article explains the Linux kernel scheduler's core concepts, walks through the initialization code of the 5.4 kernel (including run queues, scheduling classes, domains, and groups), and details how multi‑core and NUMA topologies are handled to achieve balanced CPU usage.
This comprehensive guide lists the 21 most frequently used Linux commands—from navigating directories and managing files to searching, text processing, compression, system shutdown, and process control—providing a handy cheat‑sheet for developers and system administrators alike.
This guide introduces exa, a Rust‑based, open‑source file‑listing tool that adds Git integration, colorized output, tree views, and parallel scanning to replace the classic ls command, and shows how to install and use it across major Linux distributions and macOS.
This guide explains the three Unix file timestamps, shows how to view them with stat, and demonstrates using the find command’s ‑newerXY option to locate files modified, accessed, or status‑changed after a specific date and time.
This article demystifies the three common Linux commands—ln, mv, and cp—explaining how they differ in handling inodes, dirents, and data blocks, when they create links or move files, and why their performance varies across file systems and file types.
This article explains how Linux manages physical address space using SMP and NUMA architectures, describes the node, zone, and page data structures, details page allocation via the buddy system and slab allocator, and outlines user‑ and kernel‑mode page‑fault handling, swapping, and address translation mechanisms.
This guide walks you through installing Kafka on CentOS, configuring Zookeeper, using command‑line tools, setting up the Kafka‑Eagle visual interface, and integrating Kafka with a Spring Boot application, providing code snippets and step‑by‑step instructions for a quick start.
Learn how to completely uninstall any existing MySQL, install MySQL 8.0 via dnf or yum, verify the installation, configure it to start on boot, manage root passwords, and set up remote access with Navicat, all with clear commands and screenshots.
This article explains Linux virtual memory fundamentals, covering its purpose, paging and page tables, address translation, swap usage, common issues like 32‑bit vs 64‑bit limits, and practical commands such as free, vmstat, pmap, and sysctl for monitoring and configuring memory management.
This guide explains the Linux source command, covering its syntax, how to refresh the current shell environment, execute scripts within the same session, import functions, and read variables from other scripts, with practical examples and command-line illustrations.
This article explains how to use Maven profiles to manage multiple Spring Boot environments, configure the maven‑assembly‑plugin to create a zip release containing the jar, configuration files and a custom shell script, and then deploy and control the application on Linux using the provided shenniu_publish.sh tool.
This comprehensive guide explains what HAProxy is, its core features and performance, how to install and configure it for L7 and L4 load balancing, implement health checks, session persistence, monitoring, and achieve high availability with Keepalived on Linux systems.
This article provides a detailed, step‑by‑step guide to Linux's built‑in performance monitoring utilities—top, free and vmstat—covering their purpose, essential options, output interpretation, interactive shortcuts, and practical examples for effective system administration.
This guide introduces Axel, a lightweight command‑line download accelerator for Linux, covering installation across major distributions, key configuration options, and performance comparisons with wget that demonstrate significantly faster FTP and HTTP downloads using multiple simultaneous connections.
This article explains the principles of Linux file systems using clear diagrams and the simple MINIX file system as a teaching example, covering hard‑drive basics, file and directory structures, inode layouts, formatting layout, and step‑by‑step file‑reading procedures.
This article explains the purpose of the TCP TIME_WAIT state, how it prevents packet loss and connection errors, examines its duration based on the Maximum Segment Lifetime, and analyzes why high‑QPS load testing tools like ab may appear to bypass TIME_WAIT, revealing the impact on server resources.
This article uses vivid analogies to explain the concepts of physical memory, virtual memory, and Linux's paging mechanism, showing how operating systems abstract hardware resources to simplify programming while managing limited RAM through disk-backed storage.
This guide explains why the ls command shows a fixed 4 KB size for directories, introduces the du (disk usage) utility, and provides step‑by‑step examples for obtaining total, per‑directory, per‑file, and cumulative size information using various du options.
This comprehensive guide explains what HAProxy is, its core functions and key features, then walks through installing, configuring, and running both L7 and L4 load balancers on Linux, adding logging, log rotation, monitoring, and achieving high availability with Keepalived.
This article provides a detailed walkthrough of the Calico CNI plugin source code, explaining how the calico and calico‑ipam binaries are built, how the ADD command creates WorkloadEndpoint objects, veth pairs, routes, and sysctl settings, and how these components integrate with the Calico datastore in a Kubernetes environment.
This article provides a comprehensive overview of Linux's core components—including the kernel, shell, virtual file system, various filesystem types, directory hierarchy, disk partition schemes, mounting procedures, and linking mechanisms—while illustrating key concepts with commands, code snippets, and diagrams for practical system administration.
This comprehensive guide walks through Linux memory management, explaining CPU memory access, virtual‑to‑physical address translation, page‑table initialization, zone organization, the buddy allocator, slab allocator, vmalloc, page‑fault handling, and CMA, providing code examples and diagrams to form a complete understanding.
This article explains how Linux manages virtual memory by describing the organization of virtual and physical address spaces, the mechanisms of segmentation and paging, multi‑level page tables, and the layout of user‑mode and kernel‑mode memory, including relevant kernel code examples.
This guide explains how to troubleshoot firewalld command errors, enable VRRP multicast traffic, and fix VIP migration problems in a Keepalived high‑availability setup on CentOS 7, providing step‑by‑step commands, configuration file adjustments, and verification procedures.
This article explains Linux scheduling fundamentals, describing the task_struct fields, scheduling classes, runqueue organization, the scheduling workflow including flag setting and execution, and the details of the context_switch function that performs address‑space and register state switches.
