Ubuntu 24.04: Docker + UFW = Surprise Open Ports β Close the Hole Without Breaking Containers
On Ubuntu 24.04, Docker can bypass UFW and expose ports unexpectedly. Learn how to audit, diagnose, and fix it without breaking containers.
Debian 13 minimal firewall profile: what to allow and what to drop (no paranoia)
A practical Debian 13 firewall baseline: default-deny inbound, allow essentials, keep outbound sane, and diagnose breaks fast without security theater.
MySQL vs PostgreSQL Disk-Full Incidents: Who Recovers Cleaner and Faster
A production-grade comparison of MySQL and PostgreSQL disk-full recovery: failure modes, fastest triage steps, commands, and safer storage habits.
Responsive Typography That Looks Good: clamp() Done Right
Learn practical clamp() typography: predictable scales, accessible limits, debugging tasks, and failure modesβso type feels consistent on every screen.
Debian/Ubuntu Random Timeouts: Trace the Network Path with mtr/tcpdump and Fix the Cause (Case #64)
Diagnose random network timeouts on Debian/Ubuntu using mtr and tcpdump, interpret results, isolate the hop, and fix MTU, loss, DNS, and routing.
Docker βconnection refusedβ between services: fix networks, not symptoms
Stop chasing random retries. Diagnose Docker βconnection refusedβ by proving name resolution, routes, ports, and listenersβthen fix networks.
Ubuntu 24.04: Random disconnects β debug NIC drops and offloads without superstition
Track down Ubuntu 24.04 random network disconnects by proving where packets drop: driver, offloads, IRQs, ring buffers, cables, or switches.
Why the Bottom of the GPU Market Is More Important Than You Think
Cheap GPUs shape pricing, reliability, and supply for everyone. Learn how the low end drives fleet stability, capacity planning, and outages.
Debian 13 βDevice busyβ on umount: find the holder instantly (lsof/fuser workflow)
Stop guessing why umount says βdevice busyβ on Debian 13. Use lsof, fuser, and /proc to find the holder fast and unstick cleanly.
ZFS ashift Mismatch Detection: How to Check Existing Pools
Learn how to detect ZFS ashift mismatches in existing pools, interpret outputs, and decide when to rebuild, migrate, or leave it alone safely.
When Reference Beats Custom: The Myth Thatβs Sometimes True
Custom builds can win, but reference designs often beat them in latency, reliability, and recovery. Learn when to copy, when to fork, and how to diagnose.
Ubuntu 24.04 APT is slow: cache/proxy tricks that speed up office updates
Make Ubuntu 24.04 APT updates fast in offices: diagnose bottlenecks, deploy apt-cacher-ng or proxies, tune mirrors, and stop wasting WAN bandwidth.
WordPress emails go to spam: SPF/DKIM/DMARC explained and configured
Stop WordPress emails landing in spam by fixing SPF, DKIM, and DMARC the right way. Practical tests, DNS records, and failure-mode diagnostics.
Celeron: how a cut-down chip became an upgrade legend
A production-minded deep dive into Intel Celeronβs odd rise: the parts, the myths, the benchmarks, and a practical playbook to spot CPU bottlenecks fast.
Radeonβs Origin Story: A Brand That Survived Multiple Eras
Radeon survived shifting APIs, console cycles, driver wars, and corporate mergers. Learn the history and how to diagnose GPU issues like an SRE.
Debian 13 βAddress already in useβ: find who owns the port (and fix cleanly)
Track down βAddress already in useβ on Debian 13 fast: identify the owning process, systemd unit, container, or socket, and fix it safely.
WordPress wp-config.php Mistakes: Common Misconfigurations and Fixes
Diagnose and fix common wp-config.php mistakes that break WordPress: DB errors, security gaps, cache issues, salts, prefixes, and sane hardening steps.
Intel Tick-Tock: The Strategy That Workedβ¦ Until It Didnβt
Intelβs tick-tock cadence once made capacity planning easy. Then process delays broke assumptions, reshaping performance tuning, risk, and operations.
MariaDB vs ClickHouse: Offload Analytics When Reports Are Slow
Learn how to fix slow MariaDB reporting by offloading analytics to ClickHouse: diagnostics, pitfalls, migration plan, and SRE-grade ops checks.
How Server Features Keep Sliding Into Desktop CPUs
Server-grade CPU features now ship in desktops: ECC, virtualization, telemetry, PCIe lanes, and power controls. Learn what matters and how to verify.
Fix Proxmox pvestatd.service Failed: Restore Graphs and Statistics Fast
Diagnose and fix Proxmox pvestatd.service failures that break graphs and stats: permissions, RRD corruption, storage, time drift, and cluster quirks.
Troubleshooting Proxmox Performance: CPU Steal, IO Wait, ZFS ARC, and Noisy Neighbors
Find Proxmox bottlenecks fast: CPU steal vs IO wait, ZFS ARC and swap traps, and noisy-neighbor VMsβwith commands, outputs, and decisions.
Debian 13: SSH port changed β fix firewall + sshd order without locking yourself out (case #87)
Safely change SSH port on Debian 13 without cutting your own access: correct sshd config, systemd ordering, and firewall rules with verifiable checks.
ZFS Proxmox: VM Storage Defaults You Should Change Immediately
Fix Proxmox VM storage defaults on ZFS: stop sync surprises, tune volblocksize and compression, avoid double caching, and diagnose bottlenecks fast.
Debian 13: TCP retransmits are killing performance β find where the loss really is
A practical Debian 13 guide to trace TCP retransmits to the real loss point using ss, tcpdump, ethtool, nftables, and switch clues.
ZFS RAIDZ2: The Sweet Spot for Capacity and Survival (Usually)
A practical, production-minded guide to ZFS RAIDZ2: sizing, performance, scrubs, resilver risk, and real commands to keep pools alive under pressure.
Debian 13: Permissions Chaos After rsync β The Clean Way to Preserve Ownership
Fix Debian 13 permission chaos after rsync. Learn correct flags, ownership mapping, ACL/xattr handling, NFS/root-squash gotchas, and fast diagnostics.
ZFS health dashboard: The Metrics You Must Track (or Youβre Blind)
Track the ZFS metrics that predict data loss and outages: pool health, latency, ARC, vdev balance, scrubs, SMART, fragmentation, and queueing.
ATI Before AMD: The Other School of Graphics Engineering
A practical, ops-minded look at ATIβs pre-AMD GPU engineering: drivers, pipelines, failure modes, and how to diagnose graphics bottlenecks fast.
Docker Time Zone Drift in Containers: Fix It Without Rebuilding Images
Diagnose and fix Docker container time zone drift without rebuilding images: bind-mount tzdata, set TZ safely, and validate with repeatable checks.
Email β550 5.7.1β policy blocks β the realistic fix path
A practical, ops-grade guide to fixing 550 5.7.1 policy blocks: diagnose SPF/DKIM/DMARC, IP reputation, rDNS, content, and relays with real commands.
GPU shortages: how gamers became collateral damage
A production-minded look at why GPUs stayed scarce: fabs, yield, clouds, crypto, AI, and what gamers and ops teams can do to diagnose and adapt.
Proxmox βbackup storage not available on nodeβ: why βsharedβ isnβt shared
Fix Proxmox βbackup storage not available on nodeβ by validating what βsharedβ really means: mounts, permissions, IDs, network, and config replication.
Docker Nginx upstream errors: debug 502/504 with the correct logs
Debug Docker Nginx 502/504 upstream errors fast: capture the right logs, prove the failing hop, and fix timeouts, DNS, ports, and overload safely.
WireGuard is Slow: MTU, Routing, CPU β Speed It Up Without Guesswork
Diagnose slow WireGuard with MTU, routing, CPU, and NIC checks. Use commands, interpret outputs, and apply fixes that improve throughput fast.
Best Proxmox Homelab Build in 2026: Hardware, NICs, Storage Layout, and Power Efficiency
Build a 2026 Proxmox homelab thatβs fast, quiet, and efficient: pick the right CPU, NICs, ZFS layout, SSD/HDD tiers, and checks to avoid outages.
Docker βPermission Deniedβ on Sockets and Devices: Capabilities vs Privileged, Done Right
Fix Docker βpermission deniedβ on /var/run/docker.sock, /dev/*, and UNIX sockets by choosing the right capabilities, groups, and security knobs.
DMARC Alignment: What It Is and How to Set It Correctly
Learn DMARC alignment (SPF/DKIM) with strict vs relaxed rules, real diagnostics, commands, and fixes to stop spoofing and reduce mail rejection.
WordPress Soft 404: Why Google Thinks So and How to Fix It
Fix WordPress soft 404s by aligning status codes, content, redirects, and caching so Googlebot stops treating real pages like errors and recrawls fast.
The lost 2D giants: Matrox, S3, Tsengβand why they mattered
Matrox, S3, and Tseng shaped crisp 2D, stable drivers, and predictable desktops. Learn what they did right and diagnose 2D bottlenecks today.
Why Upscaling Is the Future Even If You Hate It
Upscaling wins because shipping native pixels is expensive. Learn real bottlenecks, failure modes, and an SRE playbook to deploy it safely.
ZFS Sparse Volumes: The Overcommit Trap and How to Monitor It
Sparse ZFS zvols make overcommit easyβand outages easier. Learn the real failure modes, monitoring signals, and commands to stay ahead.
WordPress caching that doesnβt break carts and forms
Stop WordPress cache from breaking carts, logins, and forms. A production-grade guide to exclusions, headers, plugins, CDN rules, and fast diagnosis.
Debian 13: APT is broken (βunmet dependenciesβ) β fix it without reinstalling anything
Repair Debian 13 APT unmet dependencies safely: diagnose sources, pins, partial upgrades, held packages, and broken dpkg stateβno reinstall required.
WordPress 502 Bad Gateway: PHP-FPM, Nginx, Cloudflare β How to Find the Culprit
Track down WordPress 502 errors across Cloudflare, Nginx, and PHP-FPM with fast checks, commands, log patterns, and fixes that hold up in production.
Ubuntu 24.04: CIFS is painfully slow β the mount options that usually fix throughput (case #22)
Fix painfully slow CIFS on Ubuntu 24.04 with proven mount options, fast bottleneck checks, and hard-won SRE diagnostics and pitfalls.
MySQL vs ClickHouse for Realtime Dashboards: Build Fast Without Taking Down Checkout
How to run realtime dashboards without hurting MySQL checkout: choose ClickHouse wisely, design pipelines, and debug bottlenecks with SRE-grade playbooks.
ZFS zpool status -v: Finding the Exact File Thatβs Corrupt
Learn how to use zpool status -v and related ZFS tools to trace checksum errors to exact files, validate fixes, and prevent repeat corruption.
Networking on Proxmox vs ESXi: VLAN trunking, bridges/vSwitches, bonding/LACP explained
Learn how Proxmox Linux bridges compare to ESXi vSwitches, with VLAN trunks, bonding/LACP, fast troubleshooting, and real failure stories.
Fix Proxmox pve-firewall.service Failed Without Locking Yourself Out
Diagnose and fix Proxmox pve-firewall.service failed safely, keep console access, validate rules, and restore cluster networking without lockouts.