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.
Hugo publication flags decide what enters the artifact
Hugo decides which pages to render when a build runs. Front matter supplies publication metadata, configuration and command flags supply inclusion rules, and the build clock supplies the time used for evaluation. The deployed directory then stays unchanged until another artifact replaces it. A date reaching midnight is not itself a deployment event, and a file without draft: true is not automatically a draft.
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iotop shows which process is burning the disks
A disk that spikes with no obvious writer is hard to chase; iotop maps throughput straight back to the task doing the damage. System-wide tools show the symptom — high await, saturated utilization — but never the suspect: fifty processes share the disk and the average blames all of them equally. The question that ends the investigation is always per-process — who, how much, since when — and iotop answers exactly that, live, from kernel counters no application can hide from.
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A microcache serves fresh entries briefly and coalesces misses explicitly
A microcache keeps reusable responses for a short freshness lifetime, often a few seconds. Requests for the same selected representation can reuse a fresh entry during that window. The response might lag a new origin update, but it is not HTTP-stale merely because it came from a cache. Expiration, permission to serve stale content, and concurrent cache filling are separate policies.
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etcd elects a leader so writes happen in order
etcd is a replicated log, and Raft is the algorithm that keeps the replicas identical. One member is leader for a term and is the only one allowed to propose entries; an entry is committed once a majority has it. Leader election decides who may write, and log replication decides what is durable — separate mechanisms with separate failure modes.
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BPF tracepoints peek inside the running kernel
BPF and kernel tracepoints let you observe behavior at the source with a tiny footprint: no agent, no restart, no stopping the workload. Traditional profiling means installing something, restarting with flags, or pausing the process — each of which perturbs the system under study or is forbidden in production. A BPF probe attaches to an already-running kernel, collects its answer, and detaches, leaving the workload exactly as it found it.
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InnoDB covering indexes carry the query's columns
A covering index contains the columns needed to evaluate a particular query and return its requested values. In InnoDB, secondary-index records also carry the primary-key columns, so a query can be covered without explicitly listing the primary key again in the secondary-index definition. Coverage is a relationship between one query and an index, not a permanent property that applies to every query against the table.
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DNS TTL trades repeated upstream queries against retained answers
A DNS TTL is a lifetime attached to cached data, not a refresh job scheduled for every second. A cache can reuse a valid answer while it retains that entry. After expiry, a subsequent request usually requires fresh resolution unless another configured behavior applies. An idle record need not produce an upstream query merely because its TTL has reached zero.
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Bash history is your searchable command log
A useful command history saves retyping, but it is not a complete record of everything executed. Bash normally enables history in interactive shells, and settings can exclude entries or limit retention. The searchable list in a running shell and the history file on disk are separate states. That distinction explains why a command may be visible in one terminal, absent in another, and lost when an unwritten session ends unexpectedly.
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