Ubuntu 24.04 βClock skew detectedβ β fix time sync and stop build/deploy failures (case #46)
Fix Ubuntu 24.04 βClock skew detectedβ errors by diagnosing NTP, chrony, virtualization, and drift to stop CI builds and deploys failing.
ZFS Raw Send: Replicating Encrypted Data Without Sharing Keys
Learn how ZFS raw send replicates encrypted datasets safely without sharing keys, plus commands, pitfalls, diagnostics, and real ops stories.
ZFS NFS Sync Semantics: Why Clients Change Your Write Safety
NFS clients can silently change ZFS write safety. Learn how sync, commit, SLOG, and exports interact, plus diagnostics and fixes that hold in production.
Docker βText file busyβ During Deploy: The Fix That Stops Flaky Restarts
Stop Docker deploy flakiness from βtext file busyβ errors. Learn the real causes, fast diagnostics, and durable fixes for atomic, reliable restarts.
Efficiency: why faster isn’t always better
Speed fixes demos, not incidents. Learn when βfasterβ increases cost and risk, how to find real bottlenecks, and what to tune safely in production.
Netscape vs Internet Explorer: the browser war that shaped the web
How Netscape vs Internet Explorer rewired the web: standards, security, deployments, and what SREs should still verify before shipping.
Email: HELO/EHLO wrong β fix it before providers throttle you
Misconfigured HELO/EHLO causes throttling, spam flags, and delivery delays. Learn fast diagnosis, commands, fixes, and safe rollout practices.
Debian 13 βToo many open filesβ: the correct systemd limit fix (not just ulimit)
Fix Debian 13 βToo many open filesβ properly with systemd: raise the right limits, verify in /proc, and avoid ulimit myths and hidden caps.
ZFS Kubernetes: PV Design That Wonβt Bite During Node Failures
Design ZFS-backed Kubernetes PVs that survive node failures: replication, topology, sane defaults, fast triage, and commands you can trust at 3 a.m.
0-day headlines: why one vulnerability can cause instant panic
A practical SRE guide to why 0-days trigger panic, how to verify impact fast, and how to patch safely without breaking production.
ZFS fio for VMs: Profiles That Match Reality (Not Marketing)
Build fio tests that reflect VM reality on ZFS: sync writes, small blocks, latency targets, caching traps, and repeatable diagnosis from pool to guest.
ZFS xattr: The Compatibility Choice That Changes Performance
ZFS extended attributes can be stored as files or inodes. Learn how xattr modes change latency, IOPS, backups, and how to diagnose issues fast.
Docker + Reverse Proxy: 502 Mysteries β Where the Break Really Is (and Fixes)
Track down 502 errors in Docker reverse proxies fast: pinpoint DNS, ports, networks, timeouts, TLS, health checks, and upstream crashes with fixes.
Binning: How One Die Becomes Five Price Tiers
A practical, ops-minded tour of semiconductor binning: how identical-looking dies become multiple SKUs, and what it means for reliability and performance.
486: why the built-in FPU changed everything (and nobody talks about it)
The 486βs built-in FPU rewired performance, determinism, and ops realityβchanging compilers, databases, and failure modes we still debug today.
WireGuard Windows Wonβt Connect: 10 Fixes That Solve Most Cases
A production-grade checklist to fix WireGuard on Windows: routes, DNS, MTU, firewalls, keys, services, and server-side checks with commands.
Debian 13 βStart request repeated too quicklyβ: systemd fixes that actually stick
Fix Debian 13 systemd βStart request repeated too quicklyβ failures with durable overrides, sane restart logic, and fast diagnosis commands you can trust.
Docker Orphan Containers: Why They Appear and How to Purge Safely
Learn why Docker orphan containers appear, how to identify the real owner, and purge safely without breaking prod. Includes commands, playbooks, and FAQs.
ZFS refquota: The Only Quota That Stops βUsed Space Liesβ
Learn why ZFS refquota prevents misleading βused spaceβ accounting, how it differs from quota, and how to diagnose and fix space blowups fast.
MySQL vs MariaDB Replication Failover: What Breaks in Real Life (and How to Avoid It)
A production guide to MySQL vs MariaDB replication failover: what breaks, how to diagnose quickly, and the practices that prevent bad promotions.
TGP in Laptops: The Number Brands Love to Bury
Laptop GPU performance hinges on TGP. Learn how to find real wattage, diagnose throttling, and pick models that wonβt underdeliver on the spec sheet.
Debian 13: βUnit maskedβ surprises β unmask safely and fix why it got masked (case #47)
Diagnose and fix βUnit is maskedβ on Debian 13 with safe unmask steps, root-cause checks, and systemd tactics to prevent repeat outages.
Email βSender address rejectedβ: authentication and policy fixes
Fix βSender address rejectedβ fast: diagnose SMTP 5xx rejects, align SPF/DKIM/DMARC, correct envelope sender, and tune MTA policy checks safely.
ZFS ARC: How ZFS Uses RAM (and Why βFree RAMβ Is a Myth)
A practical guide to ZFS ARC memory behavior: what βfree RAMβ really means, how ARC competes with apps, and how to diagnose bottlenecks fast.
Ubuntu 24.04 Boots to a Black Screen or Boot Loop: 6 Fixes That Usually Solve It
Fix Ubuntu 24.04 black screen or boot loops fast. Diagnose GPU, initramfs, Secure Boot, display manager, disks, and kernels with proven commands.
MariaDB vs Percona Server: Drop-in Replacement or Compatibility Trap?
A pragmatic SRE guide to MariaDB vs Percona Server: real compatibility gaps, migration traps, diagnostics, and commands to verify behavior in production.
WordPress Malware Suspicion: Signs, Verification, and a Cleanup Plan
Spot WordPress malware fast, verify compromise with commands, contain safely, clean thoroughly, and harden hosting so the infection doesnβt return.
ZFS L2ARC on NVMe: When Itβs Worth It (and When ARC Is Enough)
A production-minded guide to ZFS L2ARC on NVMe: what it really accelerates, how to size it, what to measure, and the mistakes to avoid.
Email DANE: When Itβs Worth It (and Why It Often Isnβt)
DANE can harden email TLS, but it adds DNSSEC complexity and operational risk. Learn when it pays off, what breaks, and how to troubleshoot fast.
Cheap PSUs: how saving $20 becomes a fireworks show
Cheap PSUs turn small savings into outages, disk corruption, and burnt gear. Learn failure modes, fast diagnosis, and practical checks to buy safely.
ZFS arcstat: The Fastest Way to See if Cache Helps
Learn how to use arcstat to prove whether ZFS ARC is helping or hurting, spot bottlenecks fast, and make safe cache decisions in production.
WireGuard full mesh: when direct office-to-office tunnels are worth it (and when not)
A practical SRE guide to WireGuard full-mesh between offices: when it beats hub-and-spoke, when it hurts, and how to diagnose routing fast.
Ubuntu 24.04 βNo route to hostβ: ARP/gateway/ACL checklist that ends the guessing (case #32)
A production-grade Ubuntu 24.04 checklist for βNo route to hostβ: ARP, gateway, routes, VLANs, ACLs, and quick commands to isolate the break.
WordPress File Permissions Errors: What 755/644 Should Be and Why
Fix WordPress permission errors by setting correct 755/644, ownership, and PHP-FPM user. Diagnose quickly with real commands and safe decisions.
ZFS dnodes and Metadata: Why Metadata Can Be Your Real Bottleneck
Learn how ZFS dnodes, metadata, and small IO drive real-world bottlenecks, and how to diagnose and fix them with practical commands.
Docker CPU at 100%: Find the Noisy Container and Cap It Properly
Practical SRE guide to trace Docker CPU spikes to the exact container, confirm the bottleneck, and apply safe CPU limits without breaking latency.
ZFS Missing Device Paths: Using by-id and WWN Like an Adult
Stop ZFS pools breaking when /dev names shift. Use stable by-id and WWN paths, diagnose missing disks fast, and migrate safely in production.
The metaverse rush: how ‘the future’ became a meme overnight
A production-minded autopsy of the metaverse rush: incentives, infra realities, and what to measure, fix, and avoid when hype meets systems.
ZFS vs Hardware RAID: Who Protects You When the Controller Lies?
A production-minded deep dive into ZFS vs hardware RAID: silent corruption, write caches, patrol reads, recovery playbooks, and the traps that hurt.
OpenVPN AUTH_FAILED: why correct credentials still fail (and what to check)
OpenVPN AUTH_FAILED can hit even with correct passwords. Learn fast diagnosis steps, server/client checks, commands, and fixes for real-world causes.
PostgreSQL vs Percona Server: debugging slowdownsβwho gives better visibility
A hard-nosed SRE guide to tracing database slowdowns in PostgreSQL vs Percona Server: what each exposes, which tools work, and what to check first.
Microsoft Zune: how βnot iPodβ became cult-famous
A practical postmortem of Microsoft Zune: why βnot iPodβ failed commercially yet won a cult. Lessons for product, ops, and ecosystems.
Overlapping Subnets Between Offices: 3 Working Solutions Without a Rebuild
Fix overlapping office subnets without renumbering: NAT, VRFs, and overlays. Includes fast diagnosis, commands, failure modes, and rollout plans.
Do 8 Cores Still Cover Everyone in 2026? The Honest Answer
Eight cores still work for many in 2026, but not by default. Learn when 8 cores fails, how to diagnose bottlenecks, and what to buy instead.
API Keys in Public Repos: The Mistake That Never Ends
Leaked API keys keep happening: how it occurs, how to detect it fast, and how to fix processes, tooling, and rotations without breaking prod.
Email Forwarding Breaks DMARC β Fix It with SRS (and Other Options)
DMARC failures after forwarding are usually predictable. Learn why SPF breaks, how SRS fixes it, and how to diagnose and deploy safely.
ZFS Resilver Priority: Rebuild Fast Without Killing Production IO
How to tune ZFS resilver priority and IO scheduling so rebuilds finish fast without wrecking latency, with diagnostics, commands, and pitfalls.
Docker βtoo many open filesβ: raising limits the right way (systemd + container)
Fix Docker βtoo many open filesβ by identifying the real limit, then raising systemd, Docker, and container ulimits safely without breaking the host.
Fix Proxmox βIOMMU not enabledβ for PCI Passthrough (VT-d/AMD-Vi) Safely
Enable VT-d/AMD-Vi on Proxmox safely: BIOS checks, kernel params, GRUB/systemd-boot, vfio modules, IOMMU groups, and rollback steps.
MySQL vs PostgreSQL Backups and Restores: Who Gets You Back Online Faster
A practical SRE-grade comparison of MySQL and PostgreSQL backup/restore speed, failure modes, and fast recovery playbooks that cut downtime.