Reduce disk write amplification across cluster (~200-350 GB/day savings) [ci skip]
- Prometheus: persist metric whitelist (keep rules) to Helm template, preventing
regression from 33K to 250K samples/scrape on next apply. Reduce retention 52w→26w.
- MySQL InnoDB: aggressive write reduction — flush_log_at_trx_commit=0, sync_binlog=0,
doublewrite=OFF, io_capacity=100/200, redo_log=1GB, flush_neighbors=1, reduced page cleaners.
- etcd: increase snapshot-count 10000→50000 to reduce WAL snapshot frequency.
- VM disks: enable TRIM/discard passthrough to LVM thin pool via create-vm module.
- Cloud-init: enable fstrim.timer, journald limits (500M/7d/compress).
- Kubelet: containerLogMaxSize=10Mi, containerLogMaxFiles=3.
- Technitium: DNS query log retention 0→30 days (was unlimited writes to MySQL).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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