A practical guide for Linux administrators that introduces nine useful monitoring and security tools—including Nethogs, IOZone, IOTop, IPtraf, IFTop, Fail2ban, NMON, MultiTail, and Nmap—providing download links, installation commands, key options, and usage examples to enhance system management and protection.
Linus Torvalds announced the stable Linux 6.0 release, highlighting over 15,000 commits, new hardware support for AMD, LoongArch, Arm64, a low‑memory F2FS mode, stable H.265 API, and Gaudi2 char/misc code, while joking about the version bump and receiving Intel’s Innovation Award.
A high‑CPU anomaly on a Spark‑enabled machine was traced through application checks, network TIME_WAIT analysis, and Airflow inspection, leading to kernel tweaks and an Airflow configuration change that finally restored normal CPU usage.
This comprehensive guide explains Linux performance optimization by defining key metrics such as throughput and latency, interpreting average load, analyzing CPU context switches, memory management, and I/O behavior, and recommending practical tools and techniques—including vmstat, pidstat, perf, and dstat—to identify and resolve bottlenecks.
This article describes a step‑by‑step process for diagnosing a Linux server that entered rescue mode after an illegal reboot, using journalctl and systemctl commands, checking disk status, repairing an XFS filesystem with xfs_repair, and safely unmounting, re‑formatting, and re‑mounting the data partition without losing existing data.
This article provides a deep, step‑by‑step exploration of Linux process creation, using Nginx’s worker forking as a concrete example, and walks through the task_struct layout, process states, PID management, address‑space handling, file system structures, namespaces, and the internal logic of the fork system call.
Using a step‑by‑step example program, this article shows how to dramatically improve Linux pipe read/write performance—from an initial 3.5 GiB/s to 65 GiB/s—by applying zero‑copy techniques, ring buffers, paging insights, vmsplice/splice system calls, huge pages, and busy‑loop optimizations.
This article provides a step‑by‑step guide to quickly set up the latest Zabbix monitoring platform using Docker, covering Docker installation, MySQL volume creation, deployment of Zabbix server, web UI, Java gateway, agents, and host configuration for comprehensive system monitoring.
This guide explains how to configure SSH reverse tunneling to connect a local machine with isolated client networks, enabling batch initialization of servers via Ansible Playbook, covering server preparation, enabling GatewayPorts, creating the tunnel, and setting up local SSH proxy configurations.
The article details Linux’s real‑time thread CPU‑selection process, explaining how priorities (0‑99 for rt, 100‑139 for CFS) set the sched_class, how functions like select_task_rq_rt, find_lowest_rq, cpupri_find_fitness and __cpupri_find build a candidate CPU mask, and how the final CPU is chosen by previous affinity, domain order, wake‑up CPU or random selection, while warning that excessive rt tasks can increase power use and cause scheduling delays.
The article shows how to transform a single‑threaded Rust STUN server into a high‑performance, multi‑core service by using Linux’s SO_REUSEPORT to bind multiple threads, assigning each to a NIC queue, and employing batch syscalls recvmmsg/sendmmsg, achieving over a million packets per second with significantly lower CPU usage.
Learn how to use the Linux command‑line utilities tr and fmt for powerful text transformation—covering character replacement, case conversion, whitespace handling, and deletion of digits or punctuation, and formatting options—through clear syntax explanations and step‑by‑step examples.
This article explains how deleted files remain on storage until overwritten, describes the role of the file allocation table and magic numbers, and provides step‑by‑step instructions for using TestDisk, command‑line tools, and secure‑delete utilities to recover or permanently erase files on Linux systems.
This guide walks you through installing Podman on CentOS 8, configuring user namespaces, creating and building a custom UBI‑based image with a Dockerfile, running containers, verifying installed tools, using interactive shells, and mounting host directories for persistent storage.
This guide walks you through checking firewall status, enabling firewalld, adding permanent ports, reloading the firewall, and using iptables on CentOS 6, providing complete command examples and tips for troubleshooting common issues.
This guide covers core Linux commands, supported file types, inter‑process communication methods, ARM exception categories, interrupt handling steps, GPIO concepts, I2C and SPI pin functions, as well as driver inspection commands, character device creation, synchronization primitives, and key kernel subsystems.
This guide explains how to analyze and troubleshoot situations where Linux systems show high load averages despite low CPU usage, covering common load analysis methods, key commands like top, vmstat, iostat, sar, and ps, and practical solutions for I/O bottlenecks and D‑state processes.
Microsoft has released a set of Linux kernel patches that add support for running nested Hyper‑V hypervisors, detailing the changes, explaining nested virtualization benefits, and noting the potential inclusion of these patches in the upcoming Linux 6.2 release.
Learn what the SSH known_hosts file does, how it stores server public keys to verify identities, how to handle host key changes, bypass prompts for multiple users, and use commands like ssh-keyscan, ssh-keygen, and StrictHostKeyChecking to securely manage SSH connections.
This guide details key Redis monitoring metrics—including performance, memory, activity, persistence, and error indicators—along with practical commands, configuration settings, and code snippets to help operators efficiently track and troubleshoot Redis instances.
This guide explains step‑by‑step how to check firewall status, enable firewalld, open specific ports, reload or restart the firewall, and modify iptables on CentOS 6 and 7, including useful commands and common pitfalls.
This guide explains why continuous Linux logging wears out SSDs, how Log2Ram redirects logs to RAM, and provides step‑by‑step commands to install, configure, and verify Log2Ram, helping you prolong disk lifespan while maintaining system diagnostics.
This article explains how to use the iptables hashlimit module to create a stateful rate‑limiting chain, details the required commands, clarifies the meaning of the --hashlimit‑upto and --hashlimit‑burst parameters, and provides an example illustrating credit‑based packet acceptance.
This guide walks you through installing and configuring NTP, using ntpdate for one‑off synchronization, troubleshooting common ntpdate errors, and setting up Chrony as an alternative NTP client, including manual time adjustments and timezone configuration on Linux systems.
This guide explains why deleted files remain recoverable, how file allocation tables and magic numbers enable recovery, and provides step‑by‑step instructions for using TestDisk, handling device names, restoring open files, and securely erasing data on Linux systems.
This guide explains the Linux wc command, covering its purpose, syntax, common options, and how to combine it with other tools, while providing step‑by‑step examples, sample output, and tips for counting lines, words, characters, bytes, and longest lines in files or streams.
This article provides a concise reference of frequently used Linux commands for compressing and extracting files in various formats such as tar, gz, bz2, zip, rar, and more, including syntax, options, and practical notes for each archive type.
This guide explains how to locate large directories or files consuming disk space on Linux servers using commands like df, du, find, and lsof, and shows how to free space occupied by deleted files or adjust reserved root space with tune2fs.
This article introduces ten fundamental Linux commands—pgrep, pstree, bc, split, nl, mkfifo, ldd, col, xmlwf, and lsof—explaining their purposes, typical use cases, and providing clear example outputs to help developers and system administrators work more efficiently on Linux systems.
This guide shows Linux administrators how to use df, du, find, lsof, and tune2fs commands to locate large directories, uncover hidden space consumed by deleted files, and adjust filesystem reserved space, with step‑by‑step examples and screenshots.
This guide walks resource‑delivery SREs through downloading the SMC client, preparing the Tencent CVM source, creating and starting a migration task in Alibaba Cloud, and monitoring progress, enabling fast, cost‑effective conversion of a 500 GB Tencent Cloud image to an Alibaba ECS image for cross‑cloud deployment.
This article from Netflix's performance engineering team outlines ten standard Linux command‑line tools and the USE method to quickly assess system health, focusing on error and saturation metrics before utilization, enabling rapid diagnosis of CPU, memory, disk, or network bottlenecks within the first minute.
This article details the investigation and resolution of a MySQL 8.0.21 client segmentation fault on CentOS 8.4, covering missing ncurses libraries, implicit function declaration warnings, pointer truncation on 64‑bit systems, core‑file generation, gdb analysis, and the steps required to rebuild the client without crashes.
This article introduces Notepad Next, an open‑source, cross‑platform Notepad++ replacement built with Qt5, outlines its key features such as folder workspaces, macro support, and language syntax highlighting, and provides Linux installation instructions via Flatpak or AppImage.
A comprehensive collection of practical Linux one‑liners—using awk, grep, sort, uniq, and netstat—to count unique IPs, track page visits, rank URLs, monitor connection states, and measure traffic from Apache access logs for effective server operations.
This guide explains why file compression matters for storage and bandwidth, then details the most common Linux compression utilities—including tar, gzip, lzma, xz, bzip2, pax, peazip, 7zip, shar, cpio, ar, iso, kgb, zpaq, and File Roller—along with installation steps, key options, and practical command examples.
This guide explains what the inxi command‑line tool is, how to install it on various Linux distributions, and demonstrates its most useful options for displaying system, battery, CPU, combined, and weather information, along with tips for customizing output colors.
This article explains the design background, performance benefits, potential drawbacks, synchronous and asynchronous mechanisms, key data structures, operational principles, illustrative examples, and critical code paths of Linux kernel file readahead, providing a comprehensive technical overview for developers and system engineers.
This article explains what cgroups, cgroupfs, and systemd are, compares their use in container runtimes, and provides step‑by‑step instructions for switching Docker’s default cgroup driver to systemd and configuring kubelet accordingly.
This guide explains what symbolic and hard links are in Linux and provides step‑by‑step commands—using rm, unlink, and appropriate options—to remove single or multiple links, including those pointing to directories, while avoiding common pitfalls.
The article explains how a MySQL 5.7 service fails to start on a CentOS 7.9 server because SELinux blocks write access to err.log, walks through log inspection, strace tracing, SELinux context analysis, and provides a simple fix by disabling SELinux.
This guide explains how to download, compile, and install the Kube-OVN FastPath kernel module on CentOS, showing steps for both 3.x and 4.x kernels, how to verify the installation with dmesg, and notes on module loading and removal.
Learn to overcome NAT limitations and create a high‑speed, peer‑to‑peer network by installing and configuring Headscale, an open‑source Tailscale controller, including server setup, certificate handling, Docker deployment, client installation across platforms, and optional DERP relay configuration for reliable connectivity.
This article showcases seven visually impressive Linux distributions—elementary OS, Deepin, Pop!_OS, Manjaro, KDE Neon, Zorin OS, and Nitrux OS—highlighting their design focus, underlying bases, key features, and providing their official website links for readers seeking an attractive desktop experience.
This article explains why Docker containers often stop right after starting by examining the Linux PID 1 init process, the behavior of foreground versus daemonized commands in Dockerfiles, and how container runtimes like containerd‑shim and runc manage the container’s main process.
Real‑world Linux server failures show that missing PAM support in SSH prevents ulimit changes, misordered pam_faillock entries break cron authentication, and custom pam_script setups for Squid require careful configuration, highlighting that module order, thorough testing, and proper hardening are essential for reliable PAM authentication.
This comprehensive guide explores Linux kernel memory management, explaining virtual and physical address concepts, the layout of process and kernel virtual memory spaces on 32‑ and 64‑bit systems, the role of mm_struct and vm_area_struct, and how ELF binaries are mapped into memory, while also detailing DRAM organization and CPU memory access.
This guide explains how to monitor Linux system performance by using core commands such as top, vmstat, iostat, and sar to evaluate CPU usage, memory allocation, I/O activity, and network traffic, while also covering load interpretation, cache behavior, huge pages, zero‑copy techniques, and practical command examples.
This guide lists popular Linux text editors and IDEs—including Vim, Nano, Geany, Emacs, Sublime Text, Atom, Brackets, Komodo Edit, gedit, and Qt Creator—provides brief feature overviews, official website links, and step‑by‑step installation commands for both Ubuntu/Mint (apt) and CentOS (yum).
The article examines the rise of domestic IT infrastructure in China, the heavy reliance on open‑source code, how licensing changes by companies affect perceived ‘国产化’, and why active community participation and strict compliance are essential for a sustainable ecosystem.
This guide walks through installing Prometheus, node_exporter, and mysql_exporter on a Linux server, editing Prometheus configuration to scrape node and MySQL metrics, verifying the setup, and creating a Grafana dashboard to visualize MySQL performance data.
This guide explains the purpose of the SSH known_hosts file, how it protects against man‑in‑the‑middle attacks, and provides practical commands and techniques for adding, updating, and removing host keys safely across multiple users.
This guide compiles practical Linux shell commands for extracting IP counts, page visit frequencies, time‑range queries, bandwidth usage, HTTP status distribution, and TCP connection states from Apache or Nginx access logs, helping administrators quickly spot traffic patterns, bottlenecks, and potential attacks.
This article explains why the Linux find command is essential for backend developers and interviewees, demonstrates how to delete log files older than a year, and walks through seven practical find usages—including name patterns, file types, timestamps, size, permissions, ownership, and executing actions on matched files.
This guide explains the SCSI protocol, compares common hard‑disk interfaces such as IDE, SCSI, and SATA, shows how to install and use the lsscsi command with its options and examples, and details Linux SCSI file nodes and logging configuration.
This article provides a detailed overview of Docker, covering its definition, core components, advantages over virtual machines, common use cases, installation steps, storage configuration, image management commands, network modes, data volumes, private registry setup, backup procedures, and MySQL deployment, all illustrated with practical command examples.
The article explains how modern Linux distributions offer a graphical interface, robust development tools, efficient command‑line workflows, and numerous practical advantages that make them a compelling, customizable, and often faster alternative to Windows for everyday and professional use.
The article explains Linux hung‑task detection, detailing both a system‑wide polling method that compares unchanged D‑state task context‑switch counts and a watchdog approach for critical processes, describes kernel implementations, analysis of real‑world hang cases, and emphasizes log analysis and parameter tuning to prevent system hangs.
This article explains the limitations of the traditional Unix fork model, introduces lightweight POSIX threads as a faster alternative, and provides a comprehensive guide to thread creation, attributes, synchronization primitives, and cleanup functions using the pthread library in Linux.
This article provides a comprehensive guide to Linux performance monitoring, covering essential tools such as vmstat, iostat, dstat, iotop, pidstat, top/htop, mpstat, netstat, ps, strace, perf and sar, with usage examples, command syntax, and explanations of the metrics they report.
This article shares practical Linux administration techniques, including using rsync to delete massive files quickly, employing Bash parameter expansion to protect rm from accidental root deletion, adding iSCSI disks in vSphere without reboot, mounting remote filesystems with sshfs, and managing supplementary groups efficiently with gpasswd.
The article explains how a senior architect leverages SSH reverse tunneling and remote port forwarding to enable a headquarters server to reach a branch office's internal web server despite restrictive network policies, detailing the commands, verification steps, and packet flow involved.
This article explains how Linux implements processes and threads, showing that both are represented by the same task_struct structure, detailing thread creation via pthread_create and clone, and comparing the kernel‑level steps—including flag handling, copy_process, and resource sharing—that differentiate threads from full processes.
This article explains seven practical uses of the Linux find command—searching by name, type, timestamps, size, permissions, ownership, and executing actions—provides clear code examples, and shows how to solve a common interview question that deletes files older than one year.
Users of Fedora 35 reported severe screen flickering after upgrading to Linux kernel 5.19.12‑100.fc35, a problem not seen in the previous 5.19.11‑100.fc35 kernel, which Intel engineers identified as a potential LCD power‑sequencing delay and fixed in kernel 5.19.13.
This guide explains how to monitor disk usage on CentOS 7, collect snapshots with iostat, sar and pidstat, troubleshoot common errors, and finally use SystemTap to pinpoint the exact process that is writing to a specific file.
This article shares practical Linux operations guidelines—including thorough testing, cautious use of destructive commands, strict backup policies, security hardening, continuous monitoring, performance tuning, and a disciplined mindset—to help avoid costly incidents and maintain stable production environments.
This guide shows how to monitor disk usage on a CentOS 7 server, collect periodic snapshots with iostat, sar and pidstat, troubleshoot atd scheduling issues, and finally use SystemTap to pinpoint the exact PID that writes to a specific file, providing complete scripts and command‑line steps.
This article provides an overview of InfiniBand and Remote Direct Memory Access (RDMA), explains their underlying protocols and hardware, and offers detailed step‑by‑step guidance for configuring InfiniBand, RDMA, RoCE, and related services on Red Hat Enterprise Linux systems.
This article explains the fundamentals of Linux interrupt handling, covering the distinction between hardware and software interrupts, the processing flow of hard IRQs, maskable versus non‑maskable interrupts, the need for deferred execution, and a deep dive into softirqs, tasklets, and workqueues with code examples and performance considerations.
This article documents a real‑world Linux server compromise, detailing the observed symptoms, forensic commands, malicious scripts, file‑locking tricks, and a step‑by‑step remediation process including SSH hardening, cron cleanup, chattr usage, and preventive security recommendations.
This guide shows how to identify a Linux process’s PID and safely terminate it using kill, killall, or pkill, covering signal options, common signals like SIGTERM and SIGKILL, and practical command examples for both foreground and background processes.
This guide walks beginners through the complete process of publishing a website online, covering domain registration and ICP filing, DNS configuration, selecting and configuring a cloud server, installing Java and Tomcat, and finally uploading the site source files via FTP.
A whimsical tale explains how Docker solves application deployment pain by using chroot/pivot_root for filesystem isolation, Linux namespaces to hide host resources, and cgroups to limit CPU, memory, and I/O, illustrating core container technologies with practical code snippets.
This article chronicles the development of operating systems from the early Z1 computer without an OS to modern platforms like Linux, Android, iOS, and Chrome OS, highlighting key milestones, innovations, and the impact on computing over the past decades.
Mist is a command‑line helper for Debian‑based systems that brings AUR‑style package discovery and management to Ubuntu and Debian, allowing users to search, install, update, and remove packages from the makedeb Package Repository with simple commands.
Linux kernel 6.0, released on October 2 by Linus Torvalds, brings major enhancements such as Rust support, ARM and RISC‑V improvements, CPU fault detection, better ACPI power management, SMB3 performance, Intel Arc GPU certification, and even Atari PC optimizations, marking it as one of the most commit‑heavy releases in recent history.
This article explains the fundamentals of Linux interrupt handling, covering hardware and software interrupt types, the IRQ processing flow, maskable versus non‑maskable interrupts, the need for deferred execution, and detailed mechanisms of softirqs, tasklets, and workqueues with practical code examples.
Drawing from three and a half years of Linux operations, this guide outlines practical standards for testing, confirming commands, avoiding concurrent edits, mandatory backups, data safety, security hardening, continuous monitoring, performance tuning, and the right mindset to keep production environments stable and secure.
This article compares macOS and Linux by exploring their histories, kernel architectures, openness, hardware requirements, software ecosystems, user experience, customizability, gaming support, package management, and update policies, helping readers decide which operating system best fits their needs.
This guide explains how to terminate Linux processes using the kill, killall, and pkill commands, covering signal types, how to find process IDs, command syntax, and practical examples for both foreground and background tasks.
This article walks through installing BIND, configuring the named.conf file, creating forward and reverse zone files, setting up a master DNS server and a slave server, starting the services, and verifying the setup with nslookup, including a fail‑over test.
The article demonstrates how to examine a running Go program’s memory layout by defining example structs, using unsafe.Sizeof/Alignof, dumping writable regions via a Bash script and GDB, and locating fields and string constants in the resulting memory dumps to verify object representation.
This article explores how Kubernetes Pods differ from simple containers by examining their underlying implementation, shared network and IPC namespaces, cgroup hierarchies, and the role of the pause sandbox, while also demonstrating how similar pod-like behavior can be achieved using Docker and cgroup tools.
This article outlines the fundamental differences between Linux and Unix, covering topics such as the non‑standard Bash shell, the absence of long‑option support in Unix, variations in Make and C compilers, the distinction between GNU and Linux, and the trademarked UNIX name, providing a concise guide for developers navigating these operating systems.
This article explains how Kubernetes forwards packets from the initial web request through pod network namespaces, the role of the pause container, veth pairs, bridges, CNI plugins, and iptables‑based service NAT, providing a step‑by‑step view of intra‑cluster and external traffic handling.
This guide explains the ping utility’s core functions, interprets its output fields such as bytes, time, and TTL, and demonstrates advanced options like -t, -a, -n, -l, -r, as well as batch pinging of IP ranges for network troubleshooting.
This article reviews the most effective Linux antivirus solutions, explains why antivirus protection is still needed on Linux servers despite the platform's inherent security, and provides detailed descriptions of each tool along with installation guidance and usage tips.
This guide explains how to use the ping utility to test connectivity, interpret bytes, time, and TTL values, and leverage advanced options like -t, -a, -n, -l, -r, as well as batch‑ping techniques for efficient network troubleshooting.
This article explains why certain Linux commands—such as rm -rf /*, overwriting partitions, moving data to /dev/null, formatting disks, fork bombs, and malicious script execution—are extremely hazardous, illustrates their destructive effects with examples, and offers practical safety recommendations to protect your system.
This article details the investigation of an unexpected native memory consumption issue in a Spring Boot service, describing how JVM and system‑level tools were used to pinpoint the leak caused by the Spring Boot loader's Inflater usage and how configuring MCC scan paths or upgrading Spring Boot eliminated the problem.
Linux futexes provide a fast userspace lock backed by a kernel wait queue, using atomic operations when uncontended and system calls such as FUTEX_WAIT, FUTEX_WAKE, and priority‑inheritance variants to manage contention, requeueing, and priority inversion via rt‑mutex structures.
This article explains how zero‑copy techniques such as DMA, sendfile, mmap and Direct I/O reduce data copies and context switches in Linux, compares their mechanisms, advantages and drawbacks, and shows typical use cases like Kafka for high‑performance I/O.
Learn how to identify and terminate Linux processes using commands like kill, killall, and pkill, including signal options, PID retrieval methods, and practical examples for both foreground and background tasks, ensuring safe and effective process management on Unix-like systems.
This article explains the evolution, principles, use cases, workflow, and limitations of eBPF, showing how programmable kernel extensions enable advanced observability, networking, and security capabilities across Linux systems and cloud‑native environments.
This article explains how Kubernetes forwards packets from the initial web request through container networking, covering the cluster's network model, Linux network namespaces, the role of the pause container, veth pairs, bridges, CNI plugins, and how services use iptables and conntrack for pod-to-pod and pod-to-service communication.
An overview of essential Linux firewall solutions—including iptables, IPCop, Shorewall, UFW, Vuurmuur, pfSense, IPFire, Smoothwall, Endian, and ConfigServer—covers their core functions, key features, and typical use cases, helping administrators choose the right tool for network protection.
This article explains why CentOS 7 is reaching end‑of‑life, reviews community and domestic alternatives such as Rocky Linux, AlmaLinux, Anolis OS, openEuler and Galaxy Kirin, and provides detailed automatic (Leapp) and manual (dnf distro‑sync) upgrade procedures with code examples for a smooth migration.
This article provides a comprehensive technical overview of DPDK, covering its architecture, core libraries, platform modules, polling and CPU‑affinity techniques, huge‑page memory management, NUMA considerations, OS tuning steps, and integration with OVS for high‑performance packet processing.
The article explains why the free command reports more memory than the available column, describes how the kernel calculates MemAvailable using min_free_kbytes and watermarks, and provides practical guidance on tuning min_free_kbytes to meet OceanBase's memory requirements.
