Linux

• Debian 13: Recover root access with rescue mode — do it without making it worse
• Docker: Start Order vs Readiness — the Approach That Prevents False Starts
• SPF/DKIM Pass but Still Spam: The Hidden Signals to Fix
• Pure CSS Skeleton Screens: Shimmer, Reduced Motion, and Performance
• WordPress 100% CPU usage: find the plugin/bot hammering your site
• Email ARC explained (the short, useful version) — when it helps forwarded mail
• Proxmox “node not in cluster”: what happened and how to rejoin correctly
• Proxmox “unable to write /etc/pve/*”: disk, pmxcfs, or permissions — how to tell
• ZFS SAS Expander Tuning: Avoiding Saturation and Link Bottlenecks
• Ubuntu 24.04: Jumbo frames break “only some” traffic — how to test and fix MTU safely
• Office VPN with Dynamic IPs: DDNS and Strategies That Don’t Fall Apart
• Storage for Virtualization on Proxmox: ZFS vs Ceph vs iSCSI vs NFS
• Proxmox NFS “stale file handle”: why it happens and how to prevent it
• WordPress REST API Blocked by a Security Plugin: Allow Safely, Not Blindly
• MySQL vs RDS MySQL: the hidden limits that bite during incidents
• PostgreSQL vs Redis for sessions, rate limits, and queues
• Proxmox “guest agent not running”: enable QEMU Guest Agent and make it stick
• Debian 13: systemd timers vs cron — switching for reliability (and avoiding common traps)
• Docker Swap Storms: Why Containers “Work” While Your Host Melts (and Fixes)
• Proxmox Windows VM Has No Network: VirtIO NIC Driver Fixes That Actually Work
• Office VPN + VoIP: How to Reduce Jitter and Latency Over Tunnels
• Debian 13: iptables vs nftables conflict — stop the silent firewall war
• Proxmox Backup “No space left on device”: why it fails even when space seems free
• WordPress + Cloudflare Cache Settings That Won’t Break wp-admin
• WordPress REST API error: what breaks REST and how to troubleshoot
• Office VPN: Allow Access to One Server/Port Only (Least Privilege)
• ZFS Using NVMe as SLOG: When It’s Perfect and When It’s Overkill
• Ubuntu 24.04 CPU Steal and Virtualization Overhead: How to Spot It and What to Do (Case #44)
• ZFS ARC vs Linux Page Cache: Who Wins and Why You Should Care
• Docker containerd/runc errors: how to debug without reinstalling
• SPF Too Many DNS Lookups: Shrink It Safely and Pass Checks
• Infinity Fabric: the invisible link that can make-or-break performance
• Docker Remote API: Don’t Accidentally Expose Root on the Internet
• Email Not Sending from WordPress/App: SMTP Relay Setup That Actually Delivers
• WireGuard Site-to-Site: Connect Two Offices Over the Internet Step by Step
• Scroll-snap galleries: smooth horizontal content without JS
• Gmail/Outlook delivery issues: the checks that matter in 2025
• DKIM body hash mismatch: the sneaky causes nobody tells you
• L2TP/IPsec Connects but No Internet: Why It Happens and How to Fix It
• Ubuntu 24.04: “Failed to start …” — the fastest systemd triage workflow (case #62)
• Ubuntu 24.04: Nginx rate limiting that won’t block real users — how to tune it
• VPN + VLAN Segmentation for Office, Warehouse, and Cameras (Without Regrets)
• Docker IOPS Starvation: Why One DB Container Makes Everything Lag
• ZFS clones: Instant Copies With Hidden Dependencies (Know This First)
• Ubuntu 24.04 disk is slow: IO scheduler, queue depth, and how to verify improvements
• WordPress Plugin Requires Newer PHP: What to Do When Hosting Is Outdated
• Debian/Ubuntu Random Timeouts: Trace the Network Path with mtr and tcpdump (Case #4)
• ZFS NVMe-only pool tuning: Latency, IRQs, and the Real Limits
• ZFS Ransomware Response: The Snapshot Playbook That Saves You
• WordPress Too Many Redirects: Fixing www/https/Cloudflare Redirect Loops