Original, source-backed articles about running small systems, static sites, HTTP, DNS, TLS, and operations.
Posts are original articles written for this site. Each one is script-free, source-backed, and tied to the same operational reality the rest of the site records: how a small, static, publicly served system is built, secured, and kept honest.
Git merge joins two diverged lines at a new commit
A merge connects histories and records a resulting project snapshot. In an ordinary merge of two diverged branches, the new commit names both prior tips as parents. Those parent links keep the earlier commits reachable, but they do not prove that the resulting files retain every intended behavior. Merging is both a graph operation and a content decision; verifying only one of those aspects leaves important mistakes undetected.
...
TCP slow start grows with acknowledged data, not merely with elapsed time
Slow start grows a TCP sender’s congestion window while it learns how much outstanding data the path can support. With enough data and suitable acknowledgments, the classic behavior is approximately exponential growth across round trips. “Doubles every RTT” is a useful simplified pattern, not an unconditional timer rule. The window changes in response to transport feedback and the implementation’s growth conditions.
...
nginx chooses the first matching regex, not a specificity score
nginx does not assign a general specificity score to every location expression. Ordinary prefixes are selected by matching length, exact locations can finish the search, and competing regex locations are evaluated in declaration order. A regex that looks narrower to a human can lose to a broader expression placed earlier. Mixing these selection rules is a common reason apparently careful routing changes affect unexpected paths.
...
Redis expiry is a deadline, eviction is a capacity policy
Expiration and eviction can both turn a successful lookup into a miss, but they answer different questions. Expiration follows a key’s deadline. Eviction removes eligible keys to respond to memory pressure. Extending a TTL cannot prevent capacity-driven eviction, and increasing memory cannot correct a deadline that the application set incorrectly.
...
Prometheus rate estimates counter growth per second
A request counter answers how many events an instrumented process has accumulated. A rate answers how quickly those events are arriving. Prometheus rate estimates average growth per second over a selected range, adjusts observed counter resets, and extrapolates toward the range boundaries. The result is useful precisely because it has a time unit, but it is not an exact reconstruction of every event between scrapes.
...
Partitioning splits one table into many pieces that look like one
Declarative partitioning lets PostgreSQL expose one logical table while storing its rows in separate partitions. The parent routes writes and provides a common query target; the physical partitions hold the data. Its strongest benefits often concern lifecycle management and selective access, but the choice also affects keys, query shape, and operational locking.
...
The Horizontal Pod Autoscaler depends on metric semantics
A HorizontalPodAutoscaler turns configured metrics into replica recommendations. Choosing the metric and its aggregation is therefore part of application design. Increasing replicas should reduce the measured pressure or increase useful throughput; otherwise the controller may spend more money without relieving the bottleneck. Set explicit minimum and maximum counts, but do not confuse a cost bound with a performance guarantee.
...
Huge pages trade allocation flexibility for translation reach
Huge pages can increase the amount of memory covered by each cached address translation. They can reduce translation overhead for suitable workloads, but the result depends on access patterns and hardware. A large allocation alone does not prove frequent TLB misses, and fewer pages needed to describe a working set does not mean those translations all fit in the processor’s TLB.
...
