Third instance of one class (hub v0.12.0, v0.73.0, this), fixed as a class.
On 2026-07-26 03:00 UTC expected_backup_missed fired on demo-felhom, demo-hp
and drill-r50 at once; the demo-felhom one reached the CUSTOMER channel
claiming "newest backup is 176h0m0s old". Nothing was wrong — three vzdump
archives were on disk. Cause: the agent backup store is in-memory, so the
R-50 fleet restart emptied `backups` until the next run, and the hub read
empty as "no backup exists".
- assessBackupFreshness returns OK/UNKNOWN/MISSED instead of `missed bool`;
absence is UNKNOWN until it outlives an anchored window. Still pure.
- store.GetHostReportsSince + monitor.newestBackupEvidence read the hubs own
retained history (bounded 7-day lookback, early-exit on fresh evidence) —
"when did I last SEE evidence of a backup?" The anchor was free: the hub
already retains 90 days. No agent change, no new persisted state.
- store.GetFirstHostReportAt anchors absence at first contact, reusing the
existing 26h threshold as the grace (no new knob, the v0.73.0 shape).
- Deferrals logged + counted; reason strings kept distinct.
- backupStaleAfter untouched; landmine recorded (a weekly PBS snapshot would
alarm six days in seven) and owned by R-82.
Tests 493->508. Red-proofs A/B/C observed and restored; A reproduces the live
message verbatim. Replayed the real 03:00 reports (600/417/77 rows): all
three now silent.
Source: documentation/audits/DIAG-backup-missed-2026-07-26.md