UN
Uptime Notes
Docs
About
Search docs…
/
Getting Started
Welcome
About this site
Hosting & VPS
The cheapest VPS that can run a real workload
Deploy a Docker Compose stack on a VPS
Monitoring & Backups
Uptime monitoring tools compared
Backups that actually restore
Hardware
Build a quiet home server for under $400
Linux Internals
How Linux schedules I/O
Postmortems
The DNS change that took us down for four hours
Reference
A field guide to log formats
Section
Postmortems
Postmortem: the DNS change that took us down for four hours
A lightly edited internal postmortem of a DNS record change that caused a four-hour outage — the timeline, the TTL caching chain that delayed the fix, and what changed afterward.
October 8, 2026