Adversarial review (gpt-5.5) of the new architecture surfaced real gaps:
Hardware-safety / storm prevention:
- Restart-storm guard: on startup, defer the first sweep if a sweep ran
< POLL_SWEEP_INTERVAL ago (persisted in Redis), so deploy-cycling can no
longer trigger back-to-back full hardware sweeps (poller.py).
- Centralize pacing in the hardware gate: POLL_DRIVE_GAP is now held after
EVERY hardware op (SMART, SES, host, MegaRAID, ledctl), not just the
enclosure-drive loop (hwgate.py); removed the now-redundant per-loop sleeps.
- Single-instance lock made atomic (Lua compare-and-set / compare-and-expire)
and the refresher is now fatal on any error + has a done-callback, so a
dropped lock can never leave two pollers sweeping concurrently (store.py,
poller.py).
- Warn loudly when POLL_CONCURRENCY > 1.
Correctness:
- Heartbeat now actually writes: cache_set omits EX when ttl<=0 (Redis
rejects EX 0), so poller meta/last_sweep_ts persists — this also enables
the restart-storm guard and the poller_fresh health flag (cache.py).
- Web image runs a single uvicorn worker so the MQTT publisher is a true
singleton (two workers shared a client_id and flapped the broker) (Dockerfile).
- LED enqueue catches Redis errors -> API returns 503, not 500 (store.py).
Deploy independence:
- build.sh takes a target (web|poller|all) so web iterations never rebuild
or repush the poller image.
Nits: drop dead SMART_CACHE_TTL constant.
Rearchitect so a single poller process is the sole owner of all SAS/SMART/
SES hardware I/O, serialized behind one gate and paced, writing results to
Redis. The API/web and MQTT publisher become pure Redis readers — they no
longer issue any subprocess and can restart freely without touching the bus.
This addresses backplane/expander stress from concurrent + restart-triggered
SMART/SES storms (the prior model re-ran a hardware sweep on every container
start, and polled sg_ses 0x02+0x07 every 60s; 0x07 errored on the IOM6/
Xyratex expanders).
- poller.py: paced sweep (inventory, SMART per-drive w/ gap, SES 0x02, ZFS,
host/MegaRAID), startup jitter, single-instance Redis lock, LED-queue worker
- services/hwgate.py: global serialization semaphore (POLL_CONCURRENCY=1)
- services/store.py: Redis as the only producer<->consumer interface + LED queue
- services/health.py: shared drive-health classifier (fixes overview double-count)
- gate smartctl/sg_ses/zpool/ledctl; drop sg_ses 0x07 from the hot path
- routers + temps read-only from the store; main.py drops the in-process poller
- compose: 3 services (privileged poller + unprivileged app + redis) w/ pacing knobs
