Linux Disk Issues in Production: Debugging and Troubleshooting

Most DevOps engineers know how to use Linux. Almost none of them know how Linux works. Tell me if this sounds familiar: You can SSH into a server. You can run commands. You can read logs. But if I ask you: “What actually happens between the moment you press Enter and the moment that process starts running?” Most people go quiet. That’s not a gap in your Linux knowledge. That’s a gap in your Linux understanding. At Nixace, we teach both. You learn the commands. But you also learn the kernel scheduler. The VFS layer. How processes inherit file descriptors. Why fork() works the way it does. What a signal actually is — not just how to send one. Why does this matter for DevOps? Because when things break — and in production, things always break — the engineer who survives is the one who understands what’s underneath. The one who doesn’t is the one filing a ticket saying “server seems slow.” Linux internals, Linux kernel, process management, system calls, file system architecture, DevOps engineering, cloud infrastructure, debugging production issues, performance tuning, backend systems, distributed systems #LinuxInternals #DevOps #CloudEngineering #SystemsThinking #NixaceTraining

🚨 The first time I opened a Linux server… I saw folders like `/bin`, `/etc`, `/var`, `/home` and thought: “What is all this? And why is everything starting with `/`?” 😅 That confusion led me to learn something very important for DevOps. 💡 𝘋𝘢𝘺 9 𝘰𝘧 𝘮𝘺 𝘋𝘦𝘷𝘖𝘱𝘴 𝘑𝘰𝘶𝘳𝘯𝘦𝘺 Today I learned about the 𝗟𝗶𝗻𝘂𝘅 𝗙𝗶𝗹𝗲 𝗦𝘆𝘀𝘁𝗲𝗺 — the structure that organizes everything inside a Linux system. --- 📖 Think of it like a 𝗺𝗮𝗽 𝗼𝗳 𝘁𝗵𝗲 𝗲𝗻𝘁𝗶𝗿𝗲 𝗼𝗽𝗲𝗿𝗮𝘁𝗶𝗻𝗴 𝘀𝘆𝘀𝘁𝗲𝗺. In Linux, everything starts from a single root directory: 👉 `/` (root) From there, the system branches into different directories, each with a specific purpose. --- Here are some important ones I learned today: 📁 /𝗯𝗶𝗻 Contains essential command binaries like `ls`, `cp`, `mv`. 📁 /𝗲𝘁𝗰 Stores system configuration files. 📁 /𝗵𝗼𝗺𝗲 Personal directories for users. 📁 /𝘃𝗮𝗿 Contains logs, cache, and variable data. 📁 /𝘂𝘀𝗿 Stores system programs and utilities. 📁 /𝘁𝗺𝗽 Temporary files used by applications. --- 🚀 𝘞𝘩𝘺 𝘵𝘩𝘪𝘴 𝘮𝘢𝘵𝘵𝘦𝘳𝘴 𝘪𝘯 𝘋𝘦𝘷𝘖𝘱𝘴? Because when you manage servers, deploy applications, or troubleshoot issues… You constantly interact with these directories. Knowing 𝘄𝗵𝗲𝗿𝗲 𝘁𝗵𝗶𝗻𝗴𝘀 𝗹𝗶𝘃𝗲 𝗶𝗻 𝗟𝗶𝗻𝘂𝘅 saves a lot of time when debugging systems. --- 🔥 𝘔𝘺 𝘣𝘪𝘨𝘨𝘦𝘴𝘵 𝘳𝘦𝘢𝘭𝘪𝘻𝘢𝘵𝘪𝘰𝘯 𝘵𝘰𝘥𝘢𝘺: Linux is not random. Every directory has a 𝘀𝗽𝗲𝗰𝗶𝗳𝗶𝗰 𝗿𝗼𝗹𝗲 𝗶𝗻 𝗸𝗲𝗲𝗽𝗶𝗻𝗴 𝘁𝗵𝗲 𝘀𝘆𝘀𝘁𝗲𝗺 𝗼𝗿𝗴𝗮𝗻𝗶𝘇𝗲𝗱 𝗮𝗻𝗱 𝘀𝘁𝗮𝗯𝗹𝗲. --- 📌 𝘚𝘮𝘢𝘭𝘭 𝘬𝘯𝘰𝘸𝘭𝘦𝘥𝘨𝘦 𝘭𝘪𝘬𝘦 𝘵𝘩𝘪𝘴 𝘣𝘦𝘤𝘰𝘮𝘦𝘴 𝘱𝘰𝘸𝘦𝘳𝘧𝘶𝘭 𝘸𝘩𝘦𝘯 𝘸𝘰𝘳𝘬𝘪𝘯𝘨 𝘸𝘪𝘵𝘩 𝘴𝘦𝘳𝘷𝘦𝘳𝘴 𝘢𝘯𝘥 𝘤𝘭𝘰𝘶𝘥 𝘪𝘯𝘧𝘳𝘢𝘴𝘵𝘳𝘶𝘤𝘵𝘶𝘳𝘦. And that’s exactly what DevOps engineers deal with daily. --- 💬 𝘋𝘦𝘷𝘖𝘱𝘴 𝘦𝘯𝘨𝘪𝘯𝘦𝘦𝘳𝘴 𝘩𝘦𝘳𝘦 — Which Linux directory confused you the most when you started? 😅 --- Learning step by step 🚀 #DevOps #Linux #LinuxFileSystem #LearningInPublic #DevOpsInsiders #TechJourney

If you're new to DevOps, understanding Linux is essential as it serves as the foundation for everything that runs. Here are the 10 Linux commands that every DevOps engineer uses daily: 1. pwd — where am I? 2. ls -la — what's here? (including hidden files) 3. cd — move around 4. cat / less — read files without opening an editor 5. grep "error" /var/log/app.log — find what matters in logs 6. top / htop — what's consuming my CPU/memory? 7. df -h — how much disk space is available? 8. chmod / chown — resolve permission errors 9. ps aux | grep nginx — is that process running? 10. curl -I https://yourapp.com — test endpoints from the terminal Pro tip: Don't just memorize these commands; use them every day on a real server or a local VM. The muscle memory develops through practice, not just reading. Which Linux command do you use the most? Share it below, and I'll compile the community's top 10. #Linux #DevOps #SysAdmin #Beginners #CloudEngineering

🚀 Day 6: Linux Internals for DevOps Engineers 👉 Logs & Debugging (How Engineers Actually Find Issues) When a system breaks… Most beginners panic or restart the service. But real engineers do something different. 👉 They check logs. Every system, every application, every request leaves a trace. And those traces are called *logs*. 📌 What I learned today: 🔹 Logs are records of system and application events 🔹 Most logs are stored in `/var/log/` 🔹 Commands like `tail -f` and `journalctl` help in real-time debugging 🔹 Logs contain the actual reason behind failures 💡 Real Scenario: Your application suddenly goes down in production. What would you do? ❌ Restart the server ✅ Check logs first Because logs might show: * “Port already in use” * “Permission denied” * “Out of memory” 🧠 Question for you: Which command would you use to monitor logs in real time? 👇 Drop your answer! 🎯 Learning Goal: To debug issues based on root cause, not guesswork. 📅 Day 7 Tomorrow: Linux Permissions & Security (Real-world access control) Let’s keep growing 🚀 #DevOps #Linux #SRE #Debugging #SystemDesign #CloudComputing #SoftwareEngineering #TechLearning #LearningInPublic #ITCareers #EngineeringMindset #CareerGrowth

🚀 Linux Storage Mastery — Visual Guide (Carousel PDF) I’ve created a structured, slide-based breakdown of core Linux storage and disk management commands — designed for practical learning and quick reference. 📘 What’s inside: • 11-page PDF (cover + 10 command slides) • Each slide = concept + command + real terminal output • Clean, developer-focused layout for fast understanding 🔧 Commands covered: lsblk · fdisk · cfdisk · parted · mkfs · mount · df · du · swapon · mkswap (+ blkid, free) 💡 Slide structure: • Clear explanation of each command • Key flags and usage patterns • Syntax-highlighted terminal examples • Pro tips for real-world scenarios 🎯 Built for: • DevOps engineers • Linux administrators • Backend developers • Students preparing for LFCS / RHCSA 📈 Why this matters: Understanding storage at the system level is critical for performance, reliability, and troubleshooting in production environments. Check out the Blog Post: https://lnkd.in/dF4_VfX2 If you're working with Linux systems, this is a solid reference to keep handy. #Linux #DevOps #SystemAdministration #CloudComputing #BackendDevelopment #LFCS #RHCSA #n8n #Automation #TechEducation

__Introduction to Linux | History, Why It’s Powerful & Architecture Today, I strengthened my Linux fundamentals by learning about its history, importance, and layered architecture, which form the base of system administration and IT infrastructure. __ A quick look at Linux history: Linux was created by Linus Torvalds in 1991 as an open-source Unix-like operating system kernel. Over the years, it has become the backbone of servers, cloud platforms, DevOps pipelines, cybersecurity tools, and supercomputers worldwide. __ Why Linux is great: - Open-source and highly customizable - Strong security and stability - Powerful command-line environment - Excellent for automation and scripting - Widely used in servers, cloud, and DevOps __ Linux Architecture Flow: Hardware → Kernel → Shell → Applications 🔹 Hardware Layer – CPU, RAM, storage, and I/O devices that provide the physical resources for the system. 🔹 Kernel Layer – The core of Linux responsible for process management, memory allocation, device drivers, file systems, and security. 🔹 Shell Layer – The command interpreter that acts as the bridge between user commands and the kernel. 🔹 Application Layer – Software such as browsers, editors, databases, and server tools where users interact directly. Understanding Linux from both the historical and architectural perspective is helping me build stronger fundamentals before moving deeper into Bash scripting, process management, and DevOps tools. #Linux #LinuxAdmin #SystemArchitecture #Kernel #Shell #DevOps #LearningJourney

🚀 Day 3: Linux Internals for DevOps Engineers 👉 Memory Management (RAM, Swap & OOM Killer) Most people think servers crash because of CPU issues… But in reality, memory is often the real problem. Linux constantly manages memory for every running process: * How much RAM to allocate * When to move data to swap * When to kill a process 📌 Key Concepts I Learned: 🔹 RAM = Fast but limited memory used by processes 🔹 Swap = Backup memory on disk (slower but useful) 🔹 OOM Killer = Automatically kills processes when memory is exhausted 💡 Real Scenario: Your application suddenly crashes without any clear error. What could be the reason? 👉 RAM was full 👉 Kernel triggered OOM Killer 👉 Your process was terminated This is something many beginners don’t realize. 🧠 Question for you: How would you check if your system is using swap memory? 👇 Drop your answer! 🎯 Learning Goal: To understand how systems behave under memory pressure in real production environments. 📅 Day 4 Tomorrow: File System Internals (Inodes, Storage & Permissions) Let’s keep going deeper 🚀

🌐 Mastering the fundamentals that power modern infrastructure Understanding common network ports is essential for every DevOps Engineer. From secure communication to application deployment and monitoring, each port plays a critical role in how systems connect and operate efficiently. Building a strong foundation in networking not only improves troubleshooting skills but also strengthens overall system design and security awareness. 🔐⚙️ Consistency in learning the basics always pays off. 💻 #DevOps #Networking #Linux #CloudComputing #AWS #Docker #Kubernetes #Jenkins #Grafana #TechSkills #Infrastructure #DevOpsEngineer

Day 6 of becoming a DevOps Engineer Navigating the Linux Filesystem - A Must-Know for Every Tech Learner In Linux, everything is organized—and everything lives somewhere for a reason. Understanding the Linux filesystem isn’t just theory. It’s a core skill for system administration, troubleshooting, and working confidently in any Linux environment. Here’s a simplified breakdown: 🔹 Core System Directories / – The root of everything. Every file and directory starts here. /bin & /usr/bin – Essential command tools like ls, cp, cat. /sbin & /usr/sbin – System-level commands (used for admin tasks). /etc – Configuration files for the system and applications. /home – Personal space for users. /root – Home directory for the superuser. /boot – Files required to start the system. 🔹 Dynamic & System Directories /dev – Represents hardware devices. /proc & /sys – Real-time system and process information. /var – Frequently changing data like logs and web files. /tmp – Temporary files (often cleared on reboot). /opt – Optional or third-party software. /lib & /usr/lib – Shared libraries for programs. /media & /mnt – Mount points for external drives. /run – Runtime system data since last boot. Key Insight: The Linux filesystem follows a structured standard, which means once you understand it, you can navigate almost any Linux system with confidence. For me, this is more than just learning directories… It’s about building a solid foundation for DevOps and Cloud Engineering. #BuildInPublic #TechJourney #Linux #DevOps #CloudComputing #TechInAfrica #TechLearning #SystemAdministration #ContinuousLearning #TSAcademy #30DaysOfLearning

If you’re learning Linux… Start with these commands. These are used daily by DevOps engineers: 📂 File & Directory ✔ ls — list files ✔ cd — change directory ✔ pwd — current path ✔ mkdir — create folder ✔ rm — delete files 📄 File Operations ✔ cp — copy ✔ mv — move/rename ✔ cat — view file ✔ nano / vim — edit 🔍 Search & Filter ✔ grep — search text ✔ find — locate files ⚙️ System & Processes ✔ ps — running processes ✔ top — system usage ✔ kill — stop process 🌐 Networking ✔ ping — check connectivity ✔ curl — API requests ✔ ss / netstat — ports 📜 Logs ✔ tail -f — live logs ✔ journalctl — system logs Simple rule: 👉 Don’t memorize 👉 Practice daily These commands = your foundation. Master them, and everything else becomes easier. Save this cheat sheet. Follow me if you want real DevOps skills (not tutorial knowledge). #Linux #DevOps #CloudComputing #CheatSheet #Engineering