deep-dive
The Cost of Saying "I'm Still Here"
Control-plane eMMCs take 13–15 GB a day. Most of it is etcd recording twenty leases saying they're still alive, at about 22 KB a time.
eMMC
cluster-observability
Teaching Prometheus to Read an eMMC
A flat line can mean a healthy eMMC or a dead collector. An arm64 exporter, eleven tested alert rules and a dashboard that tell the two apart.
deep-dive
The Disk With No S.M.A.R.T.
Six months of drive monitoring pointed at the wrong device. The one doing three times the writes has no S.M.A.R.T. at all.