Linux

Step-by-step, command-focused guide to diagnose and optimize Linux disk I/O using fio, iostat, blktrace, sysctl tweaks, scheduler and filesystem tuning.

Command-first Linux packet loss troubleshooting for servers: NICs and drivers, MTU, bonding/bridging, offloads, queues/QoS, firewall/routing, packet captures and monitoring.

Hands on Linux rootkit removal for production servers, including live forensic commands, rkhunter and chkrootkit use, persistence cleanup, and safe recovery steps.

Operational guide to secure SSH on production Linux servers with config examples, key management, two factor integration, bastion patterns, auditing, and rollback.

Step-by-step Linux systemd troubleshooting for sysadmins to diagnose and repair failed units using journalctl, systemctl, unit debugging, and safe recovery.

Practical Linux backup checklist covering data scope, storage, automation, restore testing, and security.