Crisphollow
Practical engineering writing for people who keep systems alive.
Cache Invalidation Patterns That Survive Traffic
August 25, 2026
Everyone quotes the two hard things joke; fewer people ship caches engineered against stampede. The pattern that matters most is request collapsing: when a hot key expires, exactly one worker rebuilds while everyone else serves slightly stale data, which turns a cache miss from a database incident into a mild slowdown.
Versioned keys retire most invalidation anxiety entirely. If every read composes the key from the object and a version field, 'invalidate' becomes 'write' and stale entries simply become garbage that eviction removes on its own schedule.
Structuring DNS for Reliability
September 13, 2026
Nameserver outages are devastating because they paralyze systems globally: infrastructure monitors report operational green across every host while end users cannot locate your endpoints. Mitigating this catastrophic blind spot requires standard multi-provider redundancy backed by distinct network b…
The Operator's Guide to Load Testing
June 27, 2026
Synthetic load generation consistently fails to replicate production outages because artificial traffic profiles lack real-world dynamics. Sending constant, uniformly spaced queries against a solitary URI tests that specific route in isolation. Real crashes stem from synchronized client retry spikes…
Multi-Region Failover Planning
October 17, 2026
Preparing multi-datacenter evacuation strategies happens before service interruptions occur. Determining acceptable data freshness tolerances and clarifying operational switch authority seem like administrative matters, yet they directly shape every downstream engineering decision from synchronizati…
Practical Notes on Postgres Connection Pooling
September 7, 2026
Postgres connections are heavy - each backend carries megabytes of memory and a full process - so every scaled-out installation grows a pooler, and every pooler grows a dialect. Session pooling is nearly transparent; transaction pooling is fast and unforgiving, quietly breaking session features like…
More reading
- A Practical Guide to API Rate Limiting — Engineering, July 25, 2026
- When to Choose a Queue Over a Request — Engineering, June 17, 2026
- Why Edge Caching Still Matters in 2026 — Infrastructure, September 14, 2026
About us
We are a small team of infrastructure engineers and technical writers. We publish what we learn running production systems: incident retrospectives, protocol deep-dives and tooling notes.