Linux Server Admin with Fexingo: Sysadmin, Bash, and Server Engineering

Lucas and Luna dissect the silent killer of Linux servers: memory leaks in long-running processes. They examine a real-world case where a custom Python web service consumed gigabytes of RAM over six months, masking the issue until it triggered OOM kills. The hosts walk through the specific diagnostic workflow using smem, /proc/pid/smaps, and heap profiling to pinpoint the exact allocation that nev...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna break down Linux network bonding—what it is, why it matters for server reliability, and how to configure it without losing your sanity. They walk through the main bonding modes (active-backup, balance-rr, 802.3ad), explain the traffic-balancing math behind balance-xor and balance-alb, and share hard-won lessons from real data-cente...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna tackle the practical side of full-disk encryption on Linux servers. They focus on LUKS2 and how to set up automatic unlocking with a TPM 2.0 chip, a feature that balances security with the reality of unattended reboots. The conversation covers the essentials: what LUKS is, how TPM-based unlocking works, and the trade-offs involved....

IPv6 is no longer optional, but migrating a Linux server without breaking existing services takes planning. Lucas and Luna walk through the practical steps: dual-stack configuration, firewall rules with nftables, and troubleshooting common pitfalls. They use a real-world example of moving a web server to dual-stack, covering address selection, DNS updates, and how to test connectivity with tools l...

In this episode, Lucas and Luna dive into the practical world of Linux server disk quotas, focusing on how to manage storage on shared hosting environments. They walk through the difference between user and group quotas, the XFS and ext4 filesystem support, and the exact commands to set and enforce limits using quota and setquota. They discuss real-world scenarios like runaway logs, user temp dire...

In Episode 167 of Linux Server Admin with Fexingo, Lucas and Luna dive into systemd journald persistent storage. They explain why the default volatile journal can lose critical logs on reboot, how to enable persistent storage with a simple config change, and the practical implications for server troubleshooting and audit compliance. Using a real-world example of a crashed database server, they wal...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the art of building self-healing systemd services. They explain why a simple restart directive isn't enough, how to use RestartSec and StartLimitIntervalSec to avoid crash loops, and how to combine systemd with health checks using ExecStartPre and a custom watchdog script. They also cover the difference between Restart=on...

In this episode, Lucas and Luna dive into systemd timers as a modern replacement for cron jobs on Linux servers. They explain why timers offer better integration with systemd services, more precise scheduling options, and built-in logging and dependency handling. The hosts walk through real-world examples, from simple daily backups to complex calendar-based tasks, and discuss how to debug timers u...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into LVM cache — a feature that lets you accelerate slower spinning disks with fast NVMe or SSD storage without rebuilding your filesystem. They explain how LVM cache works, using a practical example of a mail server with a 10TB HDD array and a 512GB NVMe drive. Lucas walks through the key commands and concepts: cache pools, c...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into Logical Volume Management (LVM) — the Linux storage technology that lets you resize filesystems on the fly, take snapshots, and manage disk space without downtime. They explore a real-world scenario: a database server that runs out of disk space on a Friday afternoon. Instead of panicking, you can add a new physical disk,...

In this episode, Lucas and Luna explore Landlock, the Linux security module that lets unprivileged processes sandbox themselves without root. They walk through a concrete example: running an untrusted binary that can only access a specific directory, using a simple C program and a few syscalls. They explain how Landlock compares to namespaces, cgroups, and seccomp, and why it's a game-changer for...

In this episode, Lucas and Luna dive into systemd socket activation on Linux servers, showing how to make services like SSH and web servers start on demand and save memory. They explain the difference between socket units and service units, walk through a real example with a Python HTTP server, and discuss when socket activation makes sense—and when it doesn't. Along the way, they cover the pitfal...

In this episode of Linux Server Admin, Lucas and Luna dive deep into tmpfs on Linux servers — a filesystem that lives entirely in RAM. They explain what tmpfs actually is under the hood, how it differs from ramfs and swap-backed storage, and walk through a practical setup for a web server's session cache. You'll learn the exact mount options to use, how to set size limits so you don't OOM your box...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the practical side of cgroups v2 on Linux servers. They start with a real-world scenario: a runaway process eating CPU and memory, and show how cgroups v2 can tame it. Topics include the unified hierarchy, the difference between cgroups v1 and v2, and how to create and manage cgroups with systemd and the cgroupfs interfac...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the practical side of BPF (Berkeley Packet Filter) tools for network diagnostics on Linux servers. They walk through real-world scenarios where tcpdump and bpftrace are your best friends — from tracing slow DNS queries to spotting packet drops before they become outages. You'll learn how to use bpftrace one-liners to coun...

Lucas and Luna dive into Podman, the daemonless container engine that's gaining ground as a Docker alternative. They explain how Podman's rootless architecture improves security by design, walk through the practical differences from Docker—like the pod concept and systemd integration—and share real commands for running containers without a central daemon. If you're a sysadmin curious about why som...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the world of systemd boot diagnostics. With systemd now the default init system on almost every major Linux distribution, understanding how to debug slow or failed boots is a vital skill for any sysadmin. Lucas shares a real-world story of a server that took over 10 minutes to boot, and how a combination of systemd-analyz...

In this episode, Lucas and Luna dive into tuning the Linux server TCP stack for high-throughput workloads. They explain the key socket buffers, congestion control algorithms like BBR, and kernel parameters such as tcp_rmem and tcp_wmem. Using a real-world example of a media server pushing large files, they walk through practical adjustments, how to test improvements, and common pitfalls. By the en...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into BPFtrace, a dynamic tracing tool for Linux that lets you see exactly what's happening on a live server without rebooting or recompiling. They explain how BPFtrace builds on eBPF to give you safe, low-overhead visibility into kernel and user-space events, and walk through practical examples like tracing file opens, trackin...

In this episode of Linux Server Admin, Lucas and Luna dive into systemd's built-in sandboxing features—a powerful yet often overlooked way to harden Linux servers. They explore directives like ProtectSystem, ProtectHome, PrivateTmp, NoNewPrivileges, and more, showing how these can limit the damage a compromised service can do. Using a real-world example of a web server, they demonstrate how to app...

In this episode of Linux Server Admin, Lucas and Luna dive into control groups, or cgroups, the kernel feature that underpins container resource limits and systemd resource control. You'll learn how cgroups work under the hood, why they matter for modern server workloads, and how to use systemd's built-in resource control directives to cap CPU, memory, and I/O for services and user slices. With re...

In episode 151 of Linux Server Admin, Lucas and Luna dive into network namespaces and Virtual Routing and Forwarding (VRF) on Linux servers. They explain how network namespaces give you isolated network stacks, why they're the backbone of container networking, and how VRFs let you run multiple routing tables on a single server. Using a concrete example—a server with two uplinks to different ISPs—t...

Episode 150 of Linux Server Admin with Fexingo digs into journalctl, the systemd logging tool that can make or break your debugging sessions. Lucas and Luna walk through real-world scenarios: filtering by time windows with --since and --until, using _PID and _SYSTEMD_UNIT to isolate specific services, and taming the output with json-pretty for scripted automation. They explain why the default prio...

In this episode of Linux Server Admin with Fexingo, Lucas and Luna dive into the practical side of using nftables, the modern replacement for iptables. They walk through a real-world scenario of setting up a firewall for a small web server, covering the syntax, the key differences from iptables, and common pitfalls. Lucas shares a tip about using nftables' built-in sets to efficiently manage IP li...

In this episode, Lucas and Luna dive into turning a Linux server into a high-performance router using nftables. They explain the core concepts of packet filtering, network address translation, and routing, then walk through a practical setup with a simple dual-NIC configuration. You'll learn how to configure nftables to forward traffic, set up NAT for internet sharing, and secure the router with b...