A working drawing set

Five plates that carry the whole design.

Each plate is one sheet from a working set. Move between them, then break a dependency to see which record still stands.

Foundation

One useful host

One box, one service, one owner. One backup on another failure domain. One restore that has worked. One alert path that reaches you.

Select a dependency to see what still holds when it breaks.

Plate 02, One useful hostOne box, one service, one owner. One backup on another failure domain. One restore that has worked. One alert path that reaches you. An elevation of a small maintainable service host on a shelf. Above the host, a stick figure labelled tenant represents the person the service is for. To the right of the host, a dashed line crosses a failure-domain boundary and ends at a network-attached storage elevation with two disk slots. Under everything, a restore ledger shows the invariant shape of a restore record: date, source, target, checksum result, and elapsed time. The ledger is marked example record synthetic. Right-margin annotations name the meaning of each element.PLATE 02FoundationOne useful hostREV 2026-07FAILURE DOMAIN AFAILURE DOMAIN BTENANTTHE PERSON THE SERVICE IS FORONE FLAGSHIP SERVICESVC HOSTONE OWNER, ONE PATCH CADENCEDISK 1DISK 2MIRRORED POOLSCRUB SCHEDULEDPOOL IS AVAILABILITYNOT A BACKUPNASSEPARATE POWER, SEPARATE OWNER12345FIELD ANNOTATIONS1HEALTH INDICATORGreen is reachable, not healthy.2FAN AND POWERThis runs every hour. Idle draw is a choice.3ONE OWNER, ONE SHELFOne documented recovery procedure.4ACROSS THE BOUNDARYDifferent circuit, different building.5A POOL, NOT A BACKUPA mirror is availability. The backup lives elsewhere.RESTORE RECORDA restore record is proof. A backup job status is not.EXAMPLE RECORD, SYNTHETICDATEYYYY-MM-DDA date the person can find,not just a job id.SOURCESVC HOSTWhat was restored, by role.RESTORED ONCANARY HOSTSomewhere other than thesource.CHECKSUMsha256: matchA verified match, not a jobstatus.ELAPSEDHH:MM:SSReal elapsed time on theday.

Plate 02, Foundation

One useful host

One box, one service, one owner. One backup on another failure domain. One restore that has worked. One alert path that reaches you.

  1. ONE SVC HOST

    One box, one owner, one patch cadence. The green LED means reachable, not healthy.

  2. A NAS ACROSS THE BOUNDARY

    Different circuit, different building. A mirrored pool is availability, not the backup.

  3. ONE COPY THAT LIVES ELSEWHERE

    The backup goes to the NAS. The copy that survives disaster lives on another failure domain again.

  4. ONE ALERT PATH

    The alert path lives outside the host it watches. Silence means healthy, not merely unobserved.

  5. A DATED RESTORE RECORD

    Date, source, target, checksum, elapsed. A restore record is proof. A backup job status is not.

  1. 02-hardware
  2. 03-platform
  • ● verified or healthy
  • ▲ degraded or needs attention
  • ■ failed dependency

Plate 02

One useful host

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