sysadmin – Page 2 – ITFROMZERO

OOM Killer: Why Linux Kills Your MySQL and How to Protect It

By admin April 24, 2026

When a Linux application shuts down unexpectedly, the OOM Killer is often to blame. Learn how to read dmesg logs, understand the oom_score metric, and protect MySQL and Redis from being terminated by the OS.

Fedora

Mastering Fedora Security: Managing System-Wide Encryption with update-crypto-policies

By admin April 23, 2026

Linux encryption management has never been easier. Learn how to use update-crypto-policies on Fedora to tighten TLS and SSH security for an entire enterprise-standard system.

Linux

Say Goodbye to Cron Jobs: Switching to systemd Timers for Superior Task Scheduling

By admin April 22, 2026

Learn to use systemd Timers for Linux task scheduling as a replacement for Cron Jobs. A detailed guide on configuring auto-retries, centralized logging, and resource limits.

Security

Moving from iptables to nftables: Why It’s a Mandatory Step for SysAdmins

By admin April 22, 2026

Iptables is outdated and slow. Discover how nftables optimizes firewall performance, supports IPv4/IPv6 simultaneously, and how to safely migrate your Linux system.

Linux

Boosting Linux Server I/O Performance: noatime and tuned profile Tips

By admin April 22, 2026

A quick guide to optimizing Linux I/O performance by configuring noatime and using tuned profiles to reduce system latency.

Network

Mastering Policy-Based Routing (PBR) on Linux: Route Traffic Like a Pro

By admin April 20, 2026

Don't let backup traffic clog your main connection. A detailed guide on using Policy-Based Routing (PBR) on Linux to intelligently route traffic based on source IP and Port.

Monitoring

smartmontools Guide: Diagnosing Linux Hard Drive Issues Before Your Data Vanishes

By admin April 20, 2026

Don't let your hard drive die in silence. A detailed guide on using smartmontools to diagnose HDD/SSD health on Linux and setting up automated Telegram alerts.

Security

Auditd Configuration Guide: The “Black Box” for Tracking Every Change on Linux

By admin April 20, 2026

Hackers can wipe history but they can't hide from Auditd. A guide to configuring the Linux "black box" to trace file edits, command execution, and overall server security.

Centos

The Secret to Server ‘Immortality’: Configuring HA Clusters with Pacemaker and Corosync

By admin April 17, 2026

Learn how to build a High Availability (HA) Cluster with Pacemaker and Corosync on CentOS/Rocky Linux. A detailed guide from installation and Virtual IP configuration to handling Split-brain errors.

Network

DNS Configuration on Linux: Permanently Fix Settings Being Lost After Reboot

By admin April 15, 2026

Tired of losing DNS settings in /etc/resolv.conf after every reboot? This guide shows you how to properly configure DNS on Linux using Netplan, nmcli, and systemd-resolved for long-term stability.