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 wonβt 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 βvzdump backup failedβ 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 β 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 βFast Locallyβ 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 qualityβlatency, jitter, loss, and MTUβcollect 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 β 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 βfullβ but df looks fine β inode exhaustion explained (and fixed)
Ubuntu says βNo space leftβ while df shows room? Youβre likely out of inodes. Learn fast diagnosis, commands, fixes, and prevention for 24.04.
Future CPU Security: Are Spectre-Class Surprises Over?
Spectre isnβt βpatched away.β 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 β 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 βPage with redirectβ: When Itβs Fine and When It Hurts
Learn when GSC βPage with redirectβ 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 β pick storage that wonβt 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 βBroken pipeβ errors: when itβs harmless and when itβs your first warning (case #75)
Learn when Debian 13 βBroken pipeβ 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: operationsβwhatβs 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 βGraphicsβ 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 βdatastore not foundβ: why PVE canβt see it and how to fix
Fix Proxmox PBS βdatastore not foundβ 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 ransomwareβplus 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 βStale file handleβ on NFS: why it happens and how to stop it
Diagnose and prevent NFS βStale file handleβ errors on Ubuntu 24.04 with fast checks, root causes, and safe fixes for clients and servers.
ZFS glossary: VDEV, TXG, ARC, SPAβEverything 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 βDestination folder already existsβ: fix installs without a wp-content mess
Fix WordPress βDestination folder already existsβ without breaking wp-content: diagnose permissions, leftover files, and safe reinstall paths fast.
Debian 13: Fix βToo many redirectsβ in Nginx by correcting canonical and HTTPS loops (case #71)
Stop Nginx βtoo many redirectsβ 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 safelyβno 777.
Debian 13: Disk writeback storms β 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 βpool is not healthyβ: 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 β 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.
ZFS volblocksize Migration: Why You Usually Must Recreate the ZVOL
Changing ZFS volblocksize rarely rewrites existing ZVOL data. Learn why recreation is usually required, and how to migrate safely with proven commands.
Email TLS-RPT: Get visibility into TLS failures (and fix them)
Deploy TLS-RPT to see why inbound email TLS fails, spot MITM and misconfigurations, and fix delivery issues with actionable reports.
ROPs, TMUs, SMs, and CUs: GPU Anatomy in Plain English
Understand ROPs, TMUs, SMs, and CUs in plain English, plus real commands, bottleneck diagnosis, and failure modes for production GPU systems.
Drivers That Drop Performance: The Post-Update Ritual
A practical post-update ritual for storage, network, and GPU drivers: detect regressions fast, prove the bottleneck, and roll back safely in production.
Ubuntu 24.04: Certbot renews but your app still fails β fix permissions and reload hooks
Certbot renew succeeds on Ubuntu 24.04 but your app still serves old certs or fails TLS. Fix permissions, groups, and reload hooks safely.
Ubuntu 24.04: CIFS mount says βPermission deniedβ β the exact options that fix it
Fix Ubuntu 24.04 CIFS βPermission deniedβ fast: correct vers, sec, credentials, idmap, and kernel logs to make SMB mounts work reliably.
ZFS Recordsize Migration: Changing Strategy Without Rewriting Everything
A production-minded guide to migrating ZFS recordsize strategy safely: what changes, what doesnβt, how to measure, and when to rewrite data (selectively).
PCIe 3/4/5/6: what changes for real users
A practical, ops-focused guide to PCIe 3/4/5/6: throughput, lanes, latency, NVMe and GPUs, real bottlenecks, diagnostics, and upgrade decisions.
Debian 13 Stuck in initramfs: What It Really Means and How to Get Your System Back
If Debian 13 drops you into initramfs, your root filesystem didnβt mount. Diagnose storage, UUIDs, LVM/RAID, and fix boot fast.