Senior Linux Administrator Knowledge Base

Practical reference library for administration, troubleshooting, incident response, and long-term learning.

Two modes of use

1. Learning mode — understand how Linux components work and interact.
2. Production mode — quickly diagnose a problem, choose safe next steps, and verify recovery.

Operating principle

Observe → scope → form a hypothesis → collect evidence → make the smallest safe change → verify → document.

Start here

• Troubleshooting Methodology
• Home

Main sections

• Linux Fundamentals
• Performance & Troubleshooting
• Storage & Filesystems
• Networking & DNS
• Boot & systemd
• Containers & Kubernetes
• Security & Identity
• Logging & Observability
• Operations & Resilience
• Applications & Databases

Oracle

Linux-side operational notes, not a DBA course.

• Oracle for Linux Admins
• Oracle Listener and Connections
• Oracle Alert Log and Processes
• Oracle Storage and the FRA

Browse the folders in the left explorer or use search.

New operational notes

• Time Sync and chrony
• sysctl and Resource Limits
• strace Deep Dive
• Bonds Bridges VLANs and ethtool
• SMART and Disk Health
• LUKS and Disk Encryption
• mdadm Operations
• Device Mapper Multipath
• sar and sysstat
• perf and Flame Graphs
• udev and Kernel Modules
• coredumpctl
• systemd-resolved
• firewalld Deep Dive
• SSSD and Central Identity
• cloud-init
• Out of Band and IPMI
• Local Mail for Cron and Alerts
• cron and anacron
• NetworkManager Deep Dive
• nftables Deep Dive
• bpftrace
• systemd-networkd
• Disk Quotas
• kdump and Crash Dumps
• NUMA and Memory Affinity
• iSCSI Operations
• tc and Traffic Control
• WireGuard Operations
• btrfs Operations
• ftrace Deep Dive
• fail2ban Operations
• Signals and Process Control
• fio and Storage Benchmarking
• systemd-analyze
• nf_conntrack and Connection Tracking
• IPv6 Operations
• Thin Provisioning and Snapshots
• On-Call Practices
• Certificate Automation
• Linux Capabilities
• ZFS Operations
• Policy Based Routing
• systemd-tmpfiles
• HAProxy Operations
• eBPF Deep Dive
• PostgreSQL Operational Basics
• Auditd Deep Dive