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2026-08-29
Logs that never rotate: two usual causes
The config is never read, or the process keeps writing to the old inode.
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2026-08-22
Cron runs your script with a different environment
Three entries in PATH, no profile, no LANG — and that is by design.
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2026-08-15
When the filesystem goes read-only
After an I/O error the kernel remounts ext4 read-only to stop the damage spreading.
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2026-08-08
SSH takes ten seconds to reach a prompt
Usually a reverse DNS lookup timing out, or GSSAPI looking for something absent.
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2026-08-03
Two surprises after moving from cron to systemd timers
Persistent catch-up does not behave like a missed cron job, and a stale timer keeps running without a reload.
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2026-07-28
Lots of TIME_WAIT: usually not a problem
It is the normal state of the side that closed first. Only port exhaustion matters.
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2026-07-21
High load, idle CPU
Load counts uninterruptible sleep too, so blocked I/O shows up as load.
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2026-07-15
Port in use, but no process in sight
Wrong namespace, TIME_WAIT without SO_REUSEADDR, or the kernel using it as an ephemeral port.
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2026-07-08
HSTS is a one-way door
max-age is stored in the browser; falling back to HTTP gets blocked.
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2026-07-01
An unverified backup is not a backup
The backup job is green every day; the restore has never been run.
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2026-06-24
gzip, brotli, zstd: more compression is not free
Level 9 often buys a few percent for triple the CPU.
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2026-06-21
When NTP is filtered: keeping time roughly right over HTTPS
The provider dropped UDP 123. Two HTTPS sources and a median offset are enough for TLS, and not enough for TOTP.