Ubuntu 24.04: βFailed to start β¦β β the fastest systemd triage workflow (case #62)
A production-ready systemd workflow for Ubuntu 24.04 βFailed to startβ errors: fastest checks, commands, meanings, decisions, and fixes.
Ubuntu 24.04: Nginx rate limiting that wonβt block real users β how to tune it
Tune Nginx rate limiting on Ubuntu 24.04 without blocking real users: choose keys, size zones, handle bursts, exempt logins, and debug 429s fast.
VPN + VLAN Segmentation for Office, Warehouse, and Cameras (Without Regrets)
Design a safe VPN+VLAN network for office, warehouse, and IP cameras: segmentation patterns, routing rules, diagnostics, commands, and failure stories.
Docker IOPS Starvation: Why One DB Container Makes Everything Lag
Learn why one noisy DB container can starve IOPS and stall Docker hosts. Diagnose quickly, read the kernel signals, and fix storage contention safely.
ZFS clones: Instant Copies With Hidden Dependencies (Know This First)
ZFS clones feel like free instant copies, but they create hidden dependencies. Learn how they work, how they bite, and how to run them safely.
Ubuntu 24.04 disk is slow: IO scheduler, queue depth, and how to verify improvements
Diagnose βslow diskβ on Ubuntu 24.04 by measuring latency, IO scheduler and queue depth, then proving improvements with repeatable benchmarks.
Fakes and Refurbs: How to Avoid a Ghost GPU
A field guide to spotting fake or refurbished GPUs: verify silicon, firmware, and performance with repeatable commands before they haunt prod or budgets.
WordPress Plugin Requires Newer PHP: What to Do When Hosting Is Outdated
When a WordPress plugin needs newer PHP than your host provides, diagnose safely, upgrade without downtime, or isolate with containers and staging.
‘Studio’ drivers: real benefit or just a label?
Studio GPU drivers can reduce surprises in pro apps, but theyβre not magic. Learn whatβs different, how to verify, and when to choose them.
Debian/Ubuntu Random Timeouts: Trace the Network Path with mtr and tcpdump (Case #4)
Hunt random timeouts on Debian/Ubuntu using mtr and tcpdump. Pinpoint packet loss, MTU issues, and broken paths, then fix the real cause.
ZFS NVMe-only pool tuning: Latency, IRQs, and the Real Limits
Practical ZFS tuning for NVMe-only pools: isolate latency causes across IRQs, queues, ARC, txg, and writes, with commands and decisions.
ZFS Ransomware Response: The Snapshot Playbook That Saves You
A production-grade ZFS ransomware response playbook: detect blast radius, validate snapshots, safely rollback, and harden snapshot pipelines.
WordPress Too Many Redirects: Fixing www/https/Cloudflare Redirect Loops
Diagnose and fix WordPress βToo many redirectsβ caused by www/https mismatches, Cloudflare SSL modes, proxy headers, and caching traps.
Office VPN MTU/MSS Issues: Why Large Files Hang (SMB/RDP) and How to Fix It
Learn how VPN MTU/MSS problems break SMB and RDP transfers, how to prove it with packet tests, and the safest fixes for stable office tunnels.
ZFS UPS Integration: What a Clean Shutdown Actually Protects
A clean UPS-triggered shutdown protects ZFS intent logs, transactions, and appsβnot magical hardware. Learn commands, pitfalls, and a fast diagnosis plan.
Ubuntu 24.04: High load but βnothing is using CPUβ β the iowait trap and how to confirm it
Load average lies when your CPUs are stuck waiting on disk. Confirm iowait, pinpoint the bottleneck, and fix Ubuntu 24.04 storage stalls fast.
DNS βbogus/validation failedβ: fixing upstream DNSSEC issues the practical way
A field-tested guide to diagnose and fix DNSSEC βbogus/validation failedβ errors: prove where trust breaks, mitigate safely, and stop repeat outages.
CCTV over VPN: Access Your DVR/NVR Reliably Without Exposing It to the Internet
Build reliable CCTV access over VPN: keep DVR/NVR off the internet, fix latency and routing, harden auth, and diagnose failures fast.
Group-Based Access Over One VPN: Accounting, Warehouse, IT, Different Rights
Design one VPN for accounting, warehouse, and IT with strict group rights: identity, routing, firewall, storage ACLs, audits, and fast debugging.
Integrated graphics: from βoffice onlyβ to actually useful
Modern iGPUs now handle real workloads: multi-monitor, video, light gaming, and compute. Learn how to diagnose, tune, and avoid iGPU pitfalls.
Betamax vs VHS, Tech Edition: Why Quality Doesn’t Always Win
A production-minded take on Betamax vs VHS: ecosystems, ops friction, and incentives that decide winners even when the tech is better.
ZFS zpool get feature@*: Reading Your Poolβs Real Capabilities
Learn to read ZFS pool feature flags with zpool get feature@*. Diagnose compatibility, upgrades, and performance safely with real commands.
Memory temperatures: why GDDR6X is its own problem
GDDR6X runs hotter than core temps suggest. Learn why memory hotspots happen, how to measure them, and what fixes actually work in production.
MikroTik WireGuard site-to-site: a clean template config for two offices
A production-ready MikroTik WireGuard site-to-site template for two offices: clean IP plan, firewall/NAT rules, routing, MTU, and fast diagnostics.
Why GPUs Run Hot: A Simple Explanation That Sticks
GPUs run hot because they move enormous electrical power into tiny silicon fast. Learn the real bottlenecks, fast checks, and fixes that work.
Ubuntu 24.04: Stop rebooting to βfixβ issues β how to isolate root causes properly (case #60)
A practical Ubuntu 24.04 incident workflow: fast triage, logs, CPU/memory/disk/network isolation, and fixes that beat rebooting in production.
MySQL vs Percona Server: the drop-in upgrade that can save your production
A production-focused guide to choosing MySQL vs Percona Server, upgrading safely, diagnosing bottlenecks fast, and avoiding common failures.
Proxmox βtap device already existsβ: Fix VM Start Network Conflicts Like You Mean It
Diagnose and fix Proxmox βtap device already existsβ errors: stale QEMU taps, bridge issues, ifupdown2 quirks, and safe cleanup steps.
Ubuntu 24.04 PostgreSQL autovacuum βmystery slownessβ: how to tune it safely
Track down autovacuum slowness on Ubuntu 24.04 safely: identify I/O, bloat, wraparound pressure, then tune cost, workers, and cadence with guardrails.
Ubuntu 24.04: systemd-resolved breaks Docker DNS β fix without disabling everything
Diagnose and fix Docker DNS failures on Ubuntu 24.04 caused by systemd-resolved, without disabling it. Fast checks, safe configs, and pitfalls.
Postfix βRelay access deniedβ: Fix relaying without creating an open relay
Diagnose and fix Postfix βRelay access deniedβ by permitting the right clients, domains, and authβwithout turning your MTA into an open relay.
Proxmox VLAN not working: configure a VLAN-aware bridge correctly
Fix Proxmox VLAN failures by configuring VLAN-aware bridges, trunks, and guest tagging correctly. Includes fast diagnosis and production-grade checks.
Email: Mixed DNS records β the typo that kills delivery (and the fix)
Mixed email DNS records break delivery silently: wrong MX, SPF, DKIM, or DMARC. Learn fast diagnosis, commands, fixes, and prevention checklists.
CUDA: How NVIDIA Locked In an Entire Industry
CUDA won by making GPUs programmable, then made switching painful. Learn how the lock-in works, how to diagnose it, and how to manage it safely.
P-cores vs E-cores: hybrid CPUs explained without marketing
A practical SRE guide to P-cores and E-cores: scheduling, pinning, benchmarks, and fast diagnosis steps for real workloads on hybrid CPUs.
βrm -rf /β stories: the command that became an IT horror genre
How rm -rf / became ops folklore: real failure modes, fast diagnosis, safer deletions, and corporate mini-stories that teach better production hygiene.
ZFS Using NVMe as L2ARC: When ARC Isnβt Enough
Practical guidance for using NVMe as ZFS L2ARC: sizing, tuning, commands, failure modes, and a fast diagnosis playbook for real systems.
The DirectX arms race: why drivers sometimes beat silicon
Why DirectX performance often comes from drivers, not silicon: scheduling, shader compilers, frame pacing, tools, and a practical playbook to debug it fast.
Proxmox vs VMware ESXi: which hypervisor should you use in 2026?
A 2026 field guide to choosing Proxmox or VMware ESXi: real costs, features, performance, and failure modesβwith commands to verify the truth.
ZFS Docker: Dataset Layout That Stops Layer Explosion
A practical ZFS dataset layout for Docker that avoids layer explosion, reduces snapshot churn, and makes rollbacks and cleanup predictable in production.
MySQL vs PostgreSQL: read replicasβwhen they help and when they lie
Read replicas can save your databaseβor sabotage correctness with lag and stale reads. Learn when MySQL and Postgres replicas help, lie, and how to verify.
ZFS Snapshots: The Superpower That Can Also Fill Your Pool
Learn how ZFS snapshots really consume space, how to diagnose runaway usage fast, and the exact commands to audit, prune, and prevent pool fills.
Debian 13: AppArmor blocks your service β allow what you need without disabling security
Fix Debian 13 AppArmor denials without disabling security: trace the block, update profiles safely, and prove the change with repeatable checks.
DNS SERVFAIL from Upstream: How to Prove Your Provider Is the Problem
A practical, command-heavy playbook to diagnose SERVFAIL, isolate upstream resolvers, capture proof, and escalate effectively with your DNS provider.
Docker: Blue/green on a single host β the simplest approach that works
A practical, single-host blue/green Docker deployment pattern with health checks, atomic cutovers, rollback, and failure diagnosis you can run today.
ZFS Datasets Per Workload: The Management Trick That Prevents Chaos
Stop ZFS chaos by splitting storage into datasets per workload. Set recordsize, compression, quotas, and snapshots correctlyβand debug fast.
Debian 13: Permission denied on bind mounts β fix UID/GID mapping the clean way (case #41)
Fix Debian 13 bind mount permission denied errors by aligning UID/GID mapping across hosts, containers, and NFS. Fast diagnosis and clean fixes.
DLSS explained: the biggest FPS hack of the decade
A production-minded explanation of DLSS: how it boosts FPS, what it trades off, and how to diagnose bottlenecks with real commands and fixes.
WordPress White Screen of Death (WSOD): 12 checks that actually work
A production-grade WSOD playbook: 12 checks with commands, outputs, and decisionsβcovering PHP fatal errors, plugins, themes, cache, DB, and storage.
ZFS Metadata-Only Reads: How Special VDEV Changes the Game
Learn how ZFS special vdevs turn metadata reads into fast SSD hits, how to verify placement, and how to avoid the silent foot-guns.