Ubuntu 24.04: Certificates renew but Nginx still serves the old one β why and how to fix
On Ubuntu 24.04, certs can renew while Nginx still serves the old one. Diagnose symlinks, reloads, SNI, chains, and caching to fix it fast.
MySQL vs MariaDB: Kubernetes readinessβprobes, restarts, and data safety
How MySQL and MariaDB behave under Kubernetes probes, restarts, and storage hiccupsβplus practical commands to keep data safe and pods stable.
CPUs without fans: the comeback of passive computing
Passive CPUs are back: quieter, more reliable, and often faster than you think. Learn thermal limits, deployment checks, and ops playbooks for fanless systems.
Office VPN File Sharing: Stable SMB Between Offices Without Constant Disconnects
Make SMB file sharing stable across site-to-site VPNs: tune MTU, SMB timeouts, DNS, routing, and storage to stop disconnects and slow file opens.
PostgreSQL vs RDS PostgreSQL: performance tuning you still must do (even managed)
Managed RDS PostgreSQL reduces toil, not responsibility. Learn the tuning you still must do: queries, autovacuum, IO, WAL, locks, and observability.
Nginx for WordPress: Config Mistakes That Cause 5xx Errors (and Fixes)
Track down WordPress 5xx errors caused by Nginx misconfig: FastCGI timeouts, buffers, PHP-FPM sockets, rewrites, permissions, and overloadβfixed fast.
Debian 13 SATA Link Resets: Prove Itβs the Cable or Backplane, Not Linux
A field-tested Debian 13 guide to diagnosing SATA link resets, correlating logs to hardware, and proving when cables/backplanesβnot Linuxβare guilty.
ZFS RAID Controller Passthrough: IT Mode vs HBA vs βFake HBAβ
Learn how to run ZFS safely with disk passthrough: IT mode, true HBAs, and βfake HBAsβ. Diagnose issues fast and avoid silent failure modes.
ZFS Latency Monitoring: The Graphs That Catch Disaster Early
Monitor ZFS latency like a pro: the graphs that matter, fast triage steps, runnable commands, and failure patterns that catch outages early.
PostgreSQL vs Redis: how to stop cache stampedes from melting your DB
Practical patterns to stop cache stampedes: Redis locks, request coalescing, stale-while-revalidate, and Postgres-friendly backpressure and observability.
Responsive Tables for Technical Docs That Donβt Break in Production
Build responsive doc tables with scroll containers, sticky headers, and readable code cells. Includes diagnostics, pitfalls, and ops-grade CSS.
Debian 13: /etc/pve looks empty after reboot β why mounts fail and how to recover
When /etc/pve looks empty after reboot, itβs usually a mount or cluster filesystem issue. Diagnose fast, recover safely, and prevent repeats.
Debian 13: Package pinning saved my server β how to use apt preferences without chaos
Learn Debian 13 apt pinning with practical commands, diagnostics, and failure modes. Keep stable systems sane while mixing security, backports, and repos.
Docker macvlan: Canβt Reach the Container β Fix the Classic Routing Trap
If your Docker macvlan container is reachable from the LAN but not from the host, itβs a routing trap. Diagnose quickly and fix it safely.
Proxmox Ceph Slow Ops: Locate the Bottleneck (Disk, Network, or CPU)
A practical SRE guide to diagnosing Proxmox Ceph slow ops: identify whether disks, network, or CPU is choking and fix it fast.
MySQL vs PostgreSQL: βCPU 100%ββhow to prove itβs queries, not hardware
A practical SRE playbook to prove 100% CPU is query-driven, not hardware: capture evidence, compare MySQL vs Postgres, and fix safely.
A driver update killed my FPS: how to diagnose it properly
Diagnose post-driver FPS drops with a bottleneck-first playbook: confirm the regression, measure CPU/GPU/IO, and isolate overlays, power, VRR, and shaders.
Postfix SASL auth fails: the config gotchas and the fix order
Fix Postfix SASL auth failures fast: follow a proven fix order, test each layer, decode logs, and avoid common gotchas in production.
Coil whine: why your GPU squealsβand what you can (and can’t) do
Coil whine is electrical vibration in GPU power parts. Learn how to diagnose it fast, reduce it safely, and know when an RMA is worth it.
Print Styles for Docs That Donβt Embarrass You
Design a readable print layout for documentation: hide nav, keep links useful, wrap code safely, and debug print CSS with practical commands.
Thread Director: Why the CPU Now Advises the OS
Modern CPUs now steer scheduling via Thread Director, improving performance and power on hybrid coresβif you stop guessing and start measuring.
WordPress Domain Migration Without Losing SEO: 301s, Canonicals, Sitemaps, and Zero Drama
Migrate a WordPress site to a new domain without SEO loss: map URLs, implement 301s, fix canonicals, regenerate sitemaps, and verify in prod safely.
HBM in Mainstream GPUs: Dream or Inevitability?
HBM could fix GPU memory bottlenecks, but cost, packaging yield, and segmentation block it. A practical SRE view on what changes first.
MariaDB vs SQLite Backups: Simple Restore vs Real PITR
Learn when SQLite file restores are enough and when MariaDB point-in-time recovery is non-negotiable, with real commands, pitfalls, and playbooks.
Proxmox βCanβt Remove Nodeβ: Safe Node Removal From a Cluster
Fix Proxmox βcanβt remove nodeβ safely: verify quorum, stop services, migrate workloads, clean corosync votes, and remove stale config without downtime.
GitHub-Style Code Blocks: Title Bars, Copy Buttons, Line Numbers, and Highlighted Lines
Build GitHub-like code blocks with a title bar, copy button, line numbers, and highlighted linesβwithout slowing pages or breaking accessibility.
Rspamd False Positives: Tune Spam Scoring Without Letting Junk Through
Reduce Rspamd false positives with disciplined scoring, logs, and per-domain tuning. Diagnose fast, change safely, and keep spam from sneaking back in.
Proxmox VMs Have No Internet: vmbr0 Bridge Mistakes and Quick Fixes
Fix Proxmox VMs with no internet by auditing vmbr0, routes, VLANs, firewall, and NIC offloads. Includes fast diagnosis and concrete commands.
MySQL vs MariaDB: innodb_buffer_pool_sizeβthe copy-paste tuning mistake that kills performance
Copy-pasting innodb_buffer_pool_size between MySQL and MariaDB can trigger swap storms, IO spikes, and latency. Diagnose fast and tune safely.
rDNS/PTR Missing: The Boring DNS Fix That Saves Email Deliverability
Missing rDNS/PTR records quietly wreck email deliverability. Learn how to diagnose, fix, and verify PTR/forward DNS alignment across providers safely.
PostgreSQL vs SQLite Concurrent Writers: Who Wins and Why
PostgreSQL beats SQLite for concurrent writers via MVCC and WAL. Learn locks, failure modes, and a field-tested playbook to diagnose write bottlenecks.
ZFS primarycache: Caching Rules That Stop ARC From Wasting RAM
Learn how ZFS primarycache really works, when ARC wastes RAM, and how to set caching rules per dataset with tests, commands, and fast diagnosis.
Fixing Proxmox PBS βAuthentication Failedβ: Tokens, Permissions, and Fingerprints
A practical, production-tested guide to fix Proxmox PBS authentication failures: API tokens, ACLs, cert fingerprints, and real diagnostics commands.
WordPress Media Library Looks Empty: Database Paths and URL Issues to Check
A practical SRE-grade guide to why WordPress Media Library appears empty: DB URLs, uploads paths, rewrites, permissions, offload plugins, and fixes.
MySQL vs Percona Server Monitoring: Find Killer Queries Without Guessing
Hands-on monitoring for MySQL and Percona Server: slow logs, Performance Schema, PMM, and commands to pinpoint killer queries fastβno guessing.
OpenVPN βroute addition failedβ on Windows: routing fixes that actually work
Fix OpenVPN route addition failed on Windows with a practical playbook: identify the failing route, resolve metrics, privileges, adapters, and DNS leaks.
MariaDB vs TiDB: migration promises vs production reality
A practical, SRE-led comparison of MariaDB and TiDB: what migrations promise, what production punishes, and how to diagnose bottlenecks fast.
Breached via a Test Server: the Classic Corporate Faceplant
How test servers become breach gateways: real failure patterns, fast triage steps, hardening tasks with commands, and boring controls that work.
Socket churn: when platforms become upgrade traps
Socket churn turns routine upgrades into expensive platform traps. Learn how to diagnose bottlenecks fast, measure risk, and keep your roadmap sane.
Ubuntu 24.04: UFW + Docker β lock down containers without breaking Compose (case #40)
Harden Ubuntu 24.04 UFW with Docker safely: stop unexpected container exposure, keep Compose working, and debug iptables/nft rules quickly.
Email: SPF includes are a mess β how to simplify without breaking mail
A practical SRE guide to untangling SPF include chains, staying under DNS lookup limits, and simplifying safely without breaking deliverability.
MySQL vs MariaDB on NVMe vs SATA SSD: why your DB still feels slow (and how to prove it)
NVMe didnβt fix your slow database because latency, fsync, IO patterns, and config bottlenecks still win. Measure, donβt guess, with practical commands.
Debian 13 Split DNS for VPN and LAN: a clean setup that wonβt break after reboot
A practical Debian 13 guide to split DNS for VPN and LAN using systemd-resolved, NetworkManager, and dnsmasqβstable across reboots and outages.
Ubuntu 24.04: IPv6 Breaks Random Sites β Fix Dual-Stack Properly (Donβt Just Disable IPv6)
Stop random site failures on Ubuntu 24.04 by fixing IPv6/IPv4 dual-stack: DNS, routing, MTU, RA/DHCPv6, and Happy Eyeballsβproperly.
ZFS fio for Databases: Testing Sync Writes Without Lying to Yourself
How to benchmark ZFS sync writes for databases with fio without self-deception: correct flags, ZIL/SLOG behavior, and fast bottleneck diagnosis.
Why a Cache Monster Can Beat a βFasterβ CPU
A faster CPU often loses to a bigger, smarter cache. Learn how memory hierarchy, misses, and storage I/O dominate real workloadsβand how to diagnose it.
How to Read CPU Benchmarks Without Getting Played
CPU benchmarks can mislead even pros. Learn to spot rigged comparisons, map results to real workloads, and validate performance with on-box commands.
WireGuard split tunneling: route only what you need (and keep the rest local)
Split-tunnel WireGuard safely: route only the subnets and DNS you need, keep local traffic local, and debug routing, MTU, and leaks fast.
ZFS zpool import -d: Finding Pools When Device Paths Change
Learn how zpool import -d discovers ZFS pools after device paths change, with real commands, incident stories, mistakes, and a fast diagnosis playbook.
Proxmox GPU Passthrough Black Screen: UEFI/OVMF, ROM Issues, Reset Bugs, and Proven Fixes
Fix Proxmox GPU passthrough black screens: OVMF vs SeaBIOS, ROM quirks, PCIe reset bugs, driver traps, and a fast playbook with commands.