EPYC: how AMD turned servers into a showroom
A production-minded deep dive into AMD EPYC: why it reshaped server design, what breaks first, and how to diagnose CPU, memory, PCIe, and storage bottlenecks.
MySQL vs SQLite Backups: Whoβs Easier to Recover Under Pressure
A production-minded comparison of MySQL and SQLite backups: restore speed, failure modes, tooling, and the exact commands to recover safely under pressure.
Ubuntu 24.04: VLANs donβt work β the one bridge flag most people forget
Fix Ubuntu 24.04 VLANs on Linux bridges by enabling VLAN filtering and verifying bridge/VLAN state with a fast, command-driven diagnosis plan.
ZFS vdevs: The Rule You Break Once and Regret Forever
A practical, production-tested guide to ZFS vdev design: why vdev width is destiny, how failures happen, and the commands to diagnose fast.
The βBus Factorβ Engineer: When One Person Holds the Whole System
How to spot and fix bus-factor risk in production: practical diagnostics, runbooks, commands, and habits that prevent one-person-owned systems.
PostgreSQL vs Percona Server performance myths: why βitβs fasterβ depends on workload
PostgreSQL vs Percona Server isnβt a speed contest. Learn what makes each βfaster,β how to diagnose bottlenecks, and pick the right engine.
Ubuntu 24.04: Performance tank after update β the first 6 checks that reveal the culprit
Six fast checks to pinpoint why Ubuntu 24.04 slowed after updates: CPU, I/O, memory, kernel changes, services, drivers, plus fixes and pitfalls.
286 explained: protected mode that saved PCsβand tortured developers
A practical, ops-minded tour of the 80286 protected mode: why it mattered, how it broke software, and how to diagnose real-mode vs protected-mode pain.
Ubuntu 24.04: PHP upload limits β fix upload_max_filesize where it actually matters (case #10)
Diagnose and fix PHP upload limits on Ubuntu 24.04 by finding the real bottleneck across PHP-FPM, Apache/Nginx, proxies, and app code.
Docker Env Var Precedence: Why Your Config Is Never What You Think
A production-grade guide to Docker env var precedence: where values really come from, how Compose merges them, and how to debug config drift fast.
BIOS Beep Codes: Diagnosing Hardware Failures by Sound (and Panic)
Learn to decode BIOS beep codes fast: map patterns to RAM, GPU, CPU, and power faults, run console checks, avoid traps, and restore service safely.
PostgreSQL vs ClickHouse: ETL patterns that donβt create data chaos
Practical ETL patterns for PostgreSQL and ClickHouse: avoid duplicate rows, late data surprises, slow merges, and broken metrics with sane pipelines.
The Patriot missile bug: when time drift became a battlefield problem
A production-grade autopsy of the Patriot missile time drift bug: fixed-point rounding, uptime risk, and how to prevent time sync failures at scale.
Proxmox LXC backup/restore failures: tar errors, permissions, and filesystem gotchas
Diagnose and fix Proxmox LXC backup/restore failures: tar errors, permission problems, ACL/xattr issues, ZFS gotchas, and storage quirks.
PCIe and GPUs: when x8 is fine and when it hurts
A production-minded guide to PCIe x8 vs x16 for GPUs: real bottlenecks, fast diagnosis, failure modes, and practical commands to decide.
Docker CIFS volumes are slow: the truth (and better alternatives)
CIFS in Docker often crawls due to latency, metadata chat, and caching limits. Learn fast diagnosis, hard fixes, and better storage options.
Code-Friendly Tables: Fixed vs Auto Layout, Wrapping, and Numeric Alignment
Make tables readable in terminals, wikis, and dashboards: fixed vs auto layout, wrapping rules, and numeric alignment that prevents mistakes in ops.
Wrong Cable Outages: How One Wire Stops a Datacenter
A single wrong cable can drop links, split storage paths, or brown out racks. Learn fast diagnosis, commands, and practices that prevent repeat outages.
ZFS Adding Disks: The βAdd VDEVβ Trap That Creates Imbalance
Adding disks to ZFS with βzpool addβ can permanently skew performance and risk. Learn why, how to diagnose it fast, and safer expansion plans.
Docker Container Timeouts: Tune Retries the Right Way (Not Infinite)
Stop Docker timeouts without infinite retries. Learn where latency comes from, tune retries and backoff, and diagnose networking, DNS, and storage fast.
WordPress High TTFB: Speed Up Server Response Without Magic Plugins
Fix WordPress high TTFB by measuring PHP, database, cache, and network latency. Practical commands, playbooks, and real failure modesβno magic plugins.
MariaDB vs PostgreSQL Indexing: Why βBest Practicesβ Backfire on Real Workloads
Indexing advice often ignores your workload. Learn where MariaDB and PostgreSQL diverge, how to diagnose bottlenecks fast, and what to fix first.
GPUs after 2026: five future scenariosβfrom βAI paints it allβ to βclassic rendering returnsβ
Five plausible GPU futures after 2026, from AI-first rendering to classic raster revivalβplus SRE-grade diagnostics, commands, and failure modes.
Postfix Open Relay Risk: Test It, Prove It, Close It
Learn to detect, prove, and eliminate Postfix open relay exposure with repeatable tests, log evidence, safe configs, and incident-ready checklists.
WordPress admin-ajax.php 400/403: What Blocks AJAX and How to Fix It
Fix WordPress admin-ajax.php 400/403 errors by tracing the exact blocker: WAF rules, caching, mod_security, auth, CORS, or plugin calls.
Proxmox VLAN Not Working: Trunk Ports, Linux Bridge Tagging, and βNo Networkβ Fixes
Fix Proxmox VLAN failures fast: verify switch trunks, Linux bridge VLAN filtering, tagging, MTU, and ARP routes with practical commands and symptoms.
NUMA without tears: why dual-socket isn’t ‘double fast’
Dual-socket servers can be slower than single-socket if NUMA is ignored. Learn practical diagnostics, fixes, and safer defaults for prod systems.
Will the clock-speed race return? Not how you think
Clock speed is backβbut in bursts, fabrics, and accelerators. Learn where performance really bottlenecks and how to diagnose it fast in production.
PostgreSQL vs SQLite: Reliability vs SimplicityβWhat Fails First
A production-minded comparison of PostgreSQL and SQLite: failure modes, durability, locking, backups, and fast diagnosis steps to pick safely.
Update Outages: How One Bad Patch Can Knock Out the World
A practical SRE guide to patch-driven outages: failure modes, fast diagnosis, real commands, and controls that prevent one update from taking down everything.
ZFS RAIDZ rebuild math: Why One More Failure Can Kill You
Learn the real rebuild math behind ZFS RAIDZ, why resilver risk spikes, and how to diagnose bottlenecks and prevent the next fatal disk failure.
Debian 13: MySQL slow query log β find the query thatβs silently killing you
Track down the MySQL query that quietly burns CPU and I/O on Debian 13: enable slow logs, interpret patterns, and fix root causes safely.
Proxmox Ceph PG Stuck/Inactive: What to Do Before Data Risk Escalates
A production-grade playbook for Proxmox Ceph PGs stuck/inactive: fast diagnosis, safe fixes, commands, and the mistakes that turn hiccups into data loss.
ZFS zpool status: Reading Health Like a Forensics Analyst
Learn to read zpool status like an SRE: spot silent corruption, failing disks, and performance bottlenecks fast with commands and real fixes.
Proxmox SSL certificate broke: fast ways to restore Web UI access safely
Restore Proxmox Web UI safely after a broken SSL cert: diagnose quickly, fix pveproxy, renew or replace certs, and avoid common outages.
Email Quarantine & Spam Folder Policies: Stop Losing Important Messages
Design quarantine and spam policies that prevent lost business mail. Diagnose failures fast, tune filters safely, and audit delivery with proven ops tasks.
Docker Container Keeps Restarting: Find the Real Reason in 5 Minutes
A production-grade 5-minute playbook to stop Docker restart loops: inspect exit codes, logs, healthchecks, OOM kills, and dependenciesβfast.
Lost passwords + encryption: when mistakes become permanent
Encryption turns bad habits into permanent outages. Learn how password loss happens, how to diagnose it fast, and how to design recovery that works.
Ubuntu 24.04: Resolv.conf Keeps Changing β Fix systemd-resolved/NetworkManager Properly
Stop resolv.conf from changing on Ubuntu 24.04 by fixing systemd-resolved and NetworkManager the right way, with fast diagnosis and safe configs.
OpenVPN: Set It Up Correctly (and Why Itβs Often Slower Than WireGuard)
Build a correct OpenVPN deployment, then diagnose why itβs slower than WireGuard: crypto, MTU, TCP traps, queues, and kernel fast paths.
OEM GPUs: How to Avoid Buying a βSecretly Cut-Downβ Card
Learn how to spot OEM GPUs that look legit but ship with fewer cores, slower memory, or locked firmwareβusing checks, commands, and tests.
DNS: Your DNS βworksβ but apps still fail β the caching layers you forgot exist
DNS can resolve fine yet apps still fail. Learn the hidden caches (OS, JVM, sidecars, resolvers), fast diagnosis, and fixes with commands.
Proxmox GPU Passthrough Black Screen: 10 Causes and Fixes
Fix Proxmox GPU passthrough black screens with a fast diagnosis playbook, 10 root causes, command-driven checks, and real-world lessons.
Debian 13 Dual NIC Routing: Stop Asymmetric Routes and Random Drops (Case #53)
Fix Debian 13 dual-NIC asymmetric routing and random drops using policy routing, rp_filter tuning, conntrack checks, and repeatable diagnostics.
DNS Slow Lookups on Linux: Fix systemd-resolved the Right Way
Diagnose and fix slow DNS on Linux by tuning systemd-resolved, nsswitch, and per-link DNS. Practical commands, pitfalls, and a fast playbook.
WordPress βYou are being redirectedβ: stopping SSL and cookie redirect loops
Fix WordPress redirect loops fast: SSL offload, mixed schemes, cookie domain/path, caching, proxy headers, and wp-config settings with commands.
Debian/Ubuntu: βWorks on LAN, fails on WANβ β routing/NAT checks that reveal the cause (case #85)
A practical Debian/Ubuntu playbook to diagnose βworks on LAN, fails on WANβ failures using routing, NAT, conntrack and MTU checks.
MariaDB vs PostgreSQL: CPU spikesβwho burns cores faster under peak load
A production-minded guide to MariaDB vs PostgreSQL CPU spikes: what really burns cores, how to prove it with commands, and how to fix it fast.
Proxmox firewall locked you out: restore SSH/Web UI from console without panic
Locked out of Proxmox by firewall rules? Use the console to restore SSH and Web UI safely, verify networking, and prevent repeat outages.
ZFS Write Hole Explained: Who Has It and Why ZFS Avoids It
Understand the RAID write hole, whoβs vulnerable, and how ZFS avoids it with copy-on-write, checksums, and transactional writesβplus ops playbooks.