Debian/Ubuntu “Connected, but no internet”: Routing, Gateway, and Policy Routing Fixes
Fix “connected but no internet” on Debian/Ubuntu by diagnosing routing, default gateways, DNS, and policy routing with fast commands and real-world fixes.
Ariane 5 and the Number Conversion That Destroyed a Rocket
How a single numeric conversion in reused Ariane 4 software triggered Ariane 5’s self-destruction—and the operational lessons engineers should steal.
Docker Backup Encryption: Keep Secrets Safe Without Breaking Restores
A pragmatic guide to encrypting Docker backups without losing restores: keys, pipelines, S3, volumes, databases, testing, and failure-proof runbooks.
Antennagate: when holding a phone became a headline
A practical engineering read on Antennagate: antenna physics, testing gaps, PR fallout, and reliability lessons you can apply to networks and systems.
Will Consumer PCs Get Unified GPU+NPU Designs?
Unified GPU+NPU silicon is coming to consumer PCs, but software, memory bandwidth, and reliability will decide what actually feels faster and when.
Docker Compose Rollback: The Fastest Path Back From a Bad Deploy
A pragmatic, command-first playbook to roll back bad Docker Compose deploys fast: verify images, revert tags, restore volumes, and stabilize production.
Proxmox Ceph OSD Down: Disk vs Network vs Service — Fast Identification
A production-grade playbook to quickly tell whether a Proxmox Ceph OSD is down due to disk, network, or service issues, with commands and decisions.
Stability vs Performance at Home: Where to Draw the Line
A practical guide to balancing speed and reliability in home labs: what to tune, what to leave alone, and how to diagnose bottlenecks fast.
“640 KB is enough”: The quote myth that won’t die
The “640 KB is enough” quote persists because it fits a story. Here’s what really happened—and how to prevent today’s equivalent outages.
WordPress .htaccess Broke the Site: Restore a Safe Default Properly
A production-minded guide to fix a broken WordPress .htaccess, restore safe defaults, diagnose 403/500 loops, and harden Apache safely.
Docker IPv6 in Containers: Enable It Properly (and Avoid Surprise Leaks)
A practical SRE guide to enabling IPv6 for Docker containers safely: daemon config, routing, firewalling, leak prevention, and fast diagnostics.
Laptop i7, slow as a potato: when power limits laugh at buyers
Your i7 laptop feels slow? Power limits, thermal throttling, and OEM tuning can cap performance hard. Diagnose fast with commands, then fix it safely.
WordPress Sitemap Not Indexing: Common Causes and Fixes
Fix a WordPress sitemap that won’t index: diagnose robots, redirects, caching, CDN, plugins, canonical tags, and server errors with proven commands.
Proxmox live migration fails: what to verify for network, CPU flags, and storage
A production-grade checklist to debug Proxmox live migration failures: verify network paths, CPU flags, and storage, with commands and fixes.
WordPress 503 Service Unavailable: what to check when the site is down
A production-first guide to diagnosing WordPress 503 errors fast: identify whether PHP-FPM, Nginx/Apache, database, plugins, or resources are failing.
Proxmox vzdump backup failed: 10 real causes and how to check in order
Diagnose Proxmox “vzdump backup failed” fast: the top 10 real causes, what to check first, and exact commands to prove each fix.
Proxmox SMART warnings: which attributes actually predict failure
Learn which SMART attributes truly predict disk failure in Proxmox, how to interpret warnings, and the exact commands to decide when to replace drives.
Email Queue Keeps Growing — Find the Culprit Before Mail Stops
A production-grade playbook to diagnose a growing email queue: identify bottlenecks in DNS, TLS, storage, rate limits, and MTAs before mail stops.
MariaDB vs SQLite Performance: Why “Fast Locally” Can Be Slow in Production
SQLite feels instant on a laptop, then crawls under real traffic. Learn why MariaDB behaves differently, and how to diagnose I/O, locks, and latency.
Office VPN Quality Tests: Measure Latency, Jitter, and Loss to Prove ISP Problems
A practical field guide to test office VPN quality—latency, jitter, loss, and MTU—collect evidence, isolate the bottleneck, and escalate to your ISP.
VPN security: 12 mistakes that turn a “private tunnel” into an incident
A practical SRE guide to VPN security failures: 12 real mistakes, fast diagnosis, commands, incident stories, and checklists to prevent breaches.
Ubuntu 24.04: DKMS broke after kernel update — recover drivers without downtime
Diagnose and fix DKMS driver failures after Ubuntu 24.04 kernel updates, keep GPUs/NICs/ZFS online, and recover modules safely without downtime.
Ubuntu 24.04: Disk is “full” but df looks fine — inode exhaustion explained (and fixed)
Ubuntu says “No space left” while df shows room? You’re likely out of inodes. Learn fast diagnosis, commands, fixes, and prevention for 24.04.
Future CPU Security: Are Spectre-Class Surprises Over?
Spectre isn’t “patched away.” Learn what changed in CPUs, kernels, and ops, what still leaks, and how to diagnose and reduce risk in production.
VoIP over VPN: Stop Robotic Audio with MTU, Jitter, and QoS Basics
Fix robotic VoIP over VPN by nailing MTU/MSS, jitter and bufferbloat, DSCP/QoS, and fast diagnostics with practical commands and decision points.
Docker NFS Volumes Timing Out: Mount Options That Actually Improve Stability
Stop Docker NFS volume timeouts with stable mount options, sane timeouts, and targeted diagnostics for v3/v4, locking, DNS, and network drops.
ZFS ZVOL vs Dataset: The Decision That Changes Your Future Pain
A hard-nosed guide to choosing ZFS zvols vs datasets: performance, snapshots, block size, sync, replication, tuning, and failure modes in production.
Docker Compose: Environment variables betray you — the .env mistakes that break prod
Docker Compose .env files fail in subtle ways: interpolation quirks, precedence traps, and shell assumptions. Diagnose fast, fix safely, ship reliably.
Google Search Console “Page with redirect”: When It’s Fine and When It Hurts
Learn when GSC “Page with redirect” is normal, when it blocks indexing, and how to audit redirects with curl logs, canonicals, sitemaps, and rules.
MariaDB vs SQLite for Write Bursts: Who Handles Spikes Without Drama
A production-minded comparison of MariaDB vs SQLite under write spikes: locking, durability, WAL, fsync costs, tuning, and fast diagnostics.
Dovecot: maildir vs mdbox — pick storage that won’t haunt you later
A practical, production-minded guide to Dovecot maildir vs mdbox: performance, reliability, backups, migrations, and diagnosis tasks to choose wisely.
Debian 13 “Broken pipe” errors: when it’s harmless and when it’s your first warning (case #75)
Learn when Debian 13 “Broken pipe” is harmless noise and when it signals overload, timeouts, or crashes. Includes fast triage, commands, and fixes.
Proxmox LXC Network Broken: The veth/tap Checklist That Actually Finds the Cause
A production-grade Proxmox LXC veth/tap troubleshooting checklist: bridge, firewall, MTU, VLAN, rp_filter, NAT, and kernel clues to find root cause fast.
Forgetting the Cooler Sticker: The Funniest Overheating Cause
A practical, dry-funny SRE guide to the classic CPU cooler sticker blunder: symptoms, fast diagnosis, real commands, and habits that prevent outages.
PostgreSQL vs Percona Server: operations—what’s simpler to run at 3AM
A practical 3AM ops comparison of PostgreSQL and Percona Server: backups, replication, failover, tuning, and failure diagnosis with real commands.
Programmable Shaders: When “Graphics” Became Software
A practical, ops-minded guide to programmable shaders: history, failure modes, debugging commands, fast diagnosis playbook, and reliable deployment habits.
ZFS zfs promote: Untangling Clone Chains Without Data Loss
A production-minded guide to ZFS zfs promote: how clone chains work, how to safely promote, and how to diagnose space and replication surprises.
Proxmox PBS “datastore not found”: why PVE can’t see it and how to fix
Fix Proxmox PBS “datastore not found” by checking API auth, datastore IDs, permissions, TLS, DNS, firewall, and PBS health with runnable commands.
ZFS Immutable Backups: Readonly + Snapshot Policies That Actually Hold Up
Build ZFS immutable backups with readonly datasets, snapshots, and replication that survive accidents and ransomware—plus fast diagnosis and real commands.
Debian 13 policy routing: debug ip rule and ip route without pain
Practical Debian 13 guide to ip rule/ip route policy routing: fast diagnosis, real commands, failure patterns, and safe fixes for production.
Ubuntu 24.04 “Stale file handle” on NFS: why it happens and how to stop it
Diagnose and prevent NFS “Stale file handle” errors on Ubuntu 24.04 with fast checks, root causes, and safe fixes for clients and servers.
ZFS glossary: VDEV, TXG, ARC, SPA—Everything You Pretended to Know
A production-grade ZFS glossary that explains VDEVs, TXGs, ARC, and the SPA, with real commands, failure modes, and fast diagnosis steps.
ZFS using SATA SSD as SLOG: The Cheap Upgrade That Often Fails
SATA SSD SLOG often makes ZFS sync writes slower or unsafe. Learn what SLOG really does, how it fails, and what to deploy instead.
WordPress “Destination folder already exists”: fix installs without a wp-content mess
Fix WordPress “Destination folder already exists” without breaking wp-content: diagnose permissions, leftover files, and safe reinstall paths fast.
Debian 13: Fix “Too many redirects” in Nginx by correcting canonical and HTTPS loops (case #71)
Stop Nginx “too many redirects” loops on Debian 13 by fixing canonical host and HTTPS logic, trusting proxy headers correctly, and verifying with curl.
Debian/Ubuntu Web Root Permissions: Stop 403s Without 777 (Case #69)
Fix Apache/Nginx 403 errors on Debian/Ubuntu by setting correct ownership, execute bits, groups, ACLs, and SELinux/AppArmor safely—no 777.
Debian 13: Disk writeback storms — tune vm.dirty settings without data risk (case #45)
Stop Debian 13 writeback storms by tuning vm.dirty safely: diagnose bottlenecks, pick sane thresholds, and verify latency without risking data loss.
Proxmox ZFS “pool is not healthy”: what to do before it gets worse
When Proxmox says your ZFS pool is not healthy, act fast. Diagnose errors, scrub safely, replace disks, and prevent data loss with clear steps.
Email: Mailbox full — prevent it and recover cleanly when it happens
A practical SRE guide to prevent mailbox full outages and recover safely: diagnose quotas, disks, mail queues, IMAP, and backups with commands.
Why Windows and Linux Can Give Different FPS on the Same CPU
Same CPU, different FPS: how OS schedulers, drivers, power policy, timers, memory, and I/O stacks shift frame time and latency in practice.