~/writing/tags
#linux
4 posts
The load average with a seven hour heartbeat
Every seven hours the router's load average hit 1.0 for forty five minutes. CPU was 98% idle. Nothing ran, nothing blocked, nothing was stolen. The culprit was a beat frequency between two five second clocks, and one of them was mine.
What is putting those bytes on the wire?
The storage interface on a production cluster was pulling 4 to 12x more than the public interface where client requests arrive. Getting to a defensible number meant distrusting everything, including my own profiler, which was off by 30x.
The frozen clock that nobody noticed
A GPS-disciplined NTP server stopped being disciplined, and every monitor stayed green. The giveaway was a freq_ppb value that repeated byte-for-byte across three seconds, which a live servo never does.
The game that rebooted the hypervisor
A friend's gaming VM hard-reset its Proxmox host the instant a game launched, with nothing in the logs. The cause sat below every layer we kept editing. A power transient at game launch tripped a PCIe fault and reset the box.