docs(adr): amend 0001 — controller-segment metadata snapshot: normalized identity diagnostics, vid/ssvid/transport, frozen at open, nullable

2026-08-31 21:57:54 +05:30
parent 4d332bef53
commit 305bdd4779
1 changed files with 3 additions and 1 deletions
@@ -6,6 +6,8 @@ Accepted — resolves [Define the persistent observation store and legacy migrat

 Amended by [Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12): the `endurance_baseline` field set and validation contract — derived verification, entry-time unprivileged sysfs validation, and read-time controller-segment applicability.

+Amended by [Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14): the `controller_segments` metadata snapshot — normalized identity diagnostics plus `vid`/`ssvid`/`transport` and a degraded flag, frozen at segment open, all nullable.
+
 ## Context

 Fenris today persists full SMART samples to an append-only `data/history.jsonl` beside a derived `data/hourly.jsonl`, both in the checkout, with no schema versioning and silent skipping of malformed lines. The redesign replaces the HTML dashboard with a keyboard-first TUI backed by a short-lived privileged collector on a systemd timer and an unprivileged TUI ([lifecycle research](https://git.bongbetic.com/xavierk/Fenris/src/branch/research/systemd-privilege-lifecycle/docs/research/systemd-privilege-lifecycle.md)), and projects a usage-adjusted theoretical lifespan from Data Units Written over wall-clock time with categorical confidence ([endurance research](https://git.bongbetic.com/xavierk/Fenris/src/branch/research/nvme-endurance-signals/docs/research/nvme-endurance-signals.md)). The store must support a root writer appearing every few minutes while an unprivileged reader queries concurrently, must migrate the legacy observation history idempotently and interruption-safely, and must version its schema.
@@ -19,7 +21,7 @@ Fenris today persists full SMART samples to an append-only `data/history.jsonl`
    - `hour_observations` — one row per UTC hour: the usage-habit split (`seconds_active`, `seconds_idle`, `seconds_powered_off`, `seconds_unknown`), DUW/DUR deltas, temperature min/avg/max, sample count, coverage flag. Classification thresholds belong to the projection model, not the store.
    - `day_aggregates` — one row per UTC day; the habit-evidence grain.
    - `monitoring_periods` — `started_at`, `ended_at` (NULL = open), `end_cause` enum (`user_disabled`, `migrated`, …). Powered-off time stays inside a period; deliberately disabled time does not.
-    - `controller_segments` — boundaries where controller identity changes or DUW decreases; write deltas are never computed across a segment.
+    - `controller_segments` — boundaries where controller identity changes or DUW decreases; write deltas are never computed across a segment. Each row carries a metadata snapshot frozen when the segment opens and immutable thereafter ([Decide controller-segment metadata columns](https://git.bongbetic.com/xavierk/Fenris/issues/14)): normalized `subnqn`, `sn`, `mn`, `fr`, plus `vid`, `ssvid`, `transport`, and an `identity_degraded` flag — human diagnostics, never key components (`cntlid` excluded: it distinguishes controllers within one subsystem, out of scope for a single-drive monitor). `fr` may go stale after a mid-segment firmware update; counter discontinuities belong to the DUW-monotonic axis. Every metadata column is nullable — legacy-imported segments carry `mn` with NULLs, degraded segments whatever was observed — so incompleteness stays explicit.
    - `endurance_baseline` — one active row, replaced on edit ([Define endurance-baseline provenance and validation](https://git.bongbetic.com/xavierk/Fenris/issues/12)): the rated-TBW value in bytes (`E_rated = entered_TBW × 10¹²`) plus mandatory provenance — source URL, document revision, entry date, model string, nominal capacity — and frozen validation facts (detected model, detected capacity bytes, `validated_by` `machine`/`user`, `validated_at`). Verification is derived at read — complete provenance and a drive match (machine or attested), never a stored boolean; incomplete provenance stores only behind an explicit unverified acknowledgment, as NULL fields in that precedence tier. Entry validation is an unprivileged live sysfs read of the configured device (normalized model containment with an interactive confirm recorded as `validated_by = user`; capacity within ±1%); at projection time applicability is a model match against the current controller segment, and a mismatch is retained — never auto-deleted — leaving the projection Unavailable.
    - Projections are not stored; they are recomputed on read. There is no separate latest-status table.
 4. **Day boundary**: UTC, matching hours, so day derivation from hour rows is monotonic and DST-ambiguous or 23/25-hour days never exist in the store.