Linux
Kernel behavior, system tuning, and debugging at the OS level when the application stack runs out of answers.
Engineering Notes 1
- File Descriptor Limits Under Connection Spikes
Too many open sockets crashed the gateway with 'too many open files' — ulimits, kernel tuning, and Kubernetes limits.
Debugging Stories 1
- Debugging High Load with strace and perf
P99 latency spiked but CPU was idle — tracing syscalls found we were blocked on fsync, not compute.