Core System Architecture Part 100 — Anonymous Network Disaster Recovery, Backup Integrity, Restore Orchestration, Regional Failover, Continuity Validation & Privacy-Preserving Resilience Architecture
SIAR — Secure, Local-First, Multi-Transport Communication Platform
Series: Core System Architecture
Part: 100
Status: Architecture specification
Primary language: Rust
Builds on: Core System Architecture Parts 33, 50, 57, 67, 70, 74–76, 94–99
Primary purpose: define SIAR's disaster-recovery architecture for backup integrity, restore orchestration, recovery-point validation, regional failover, tenant isolation, continuity modes, anti-rollback, deletion-barrier preservation, key custody, degraded operation, recovery drills, recovery evidence, and privacy-preserving resilience across client, server, federation, and managed deployments.
1. Purpose
Disaster recovery is not the same as backup.
A system may possess backups and still fail to recover because:
backups are corrupt
keys are missing
schemas drifted
deletion barriers were lost
restores resurrect stale data
regional failover breaks privacy guarantees
operators never tested recovery
The governing principle is:
SIAR disaster recovery must restore trustworthy service and state—not merely restore bytes—and must preserve security, privacy, deletion, tenancy, and cryptographic guarantees throughout failure and recovery.
2. Architectural Position
Production State
│
▼
Backup / Replication / Snapshots
│
▼
Integrity Verification
│
▼
Recovery Catalog
│
├── Local Restore
├── Service Restore
├── Tenant Restore
├── Regional Failover
└── Federation Recovery
│
▼
Post-Restore Validation
│
▼
Trusted Recovery
3. Core Separation
Keep distinct:
backup
snapshot
replica
restore point
failover target
recovery key
deletion barrier
continuity mode
4. Non-Goals
Part 100 does not create:
one universal backup containing all private data
automatic restore without validation
cross-tenant recovery shortcuts
silent privacy downgrade during failover
backup-based resurrection of deleted identities/data
5. Recovery Domains
#![allow(unused)] fn main() { pub enum RecoveryDomain { DeviceLocal, AccountOwned, Service, Tenant, Region, FederationPeer, Governance, } }
6. DeviceLocal
Client-local application state.
7. AccountOwned
User-owned encrypted logical backup.
8. Service
Backend service state.
9. Tenant
Managed organization state.
10. Region
Regional deployment/control-plane state.
11. FederationPeer
Federated trust/peer state.
12. Governance
High-value authority/policy state.
13. Hard Rule
Each recovery domain has separate scope, keys, and restore authority.
14. Recovery Identity
#![allow(unused)] fn main() { pub struct RecoveryId(pub [u8; 16]); }
15. Recovery Point ID
#![allow(unused)] fn main() { pub struct RecoveryPointId(pub [u8; 32]); }
16. Recovery Point
#![allow(unused)] fn main() { pub struct RecoveryPoint { pub id: RecoveryPointId, pub domain: RecoveryDomain, pub created_at: CoarseTimestamp, pub security_epoch: RecoverySecurityEpoch, pub manifest_digest: Digest, } }
17. Recovery Security Epoch
#![allow(unused)] fn main() { pub struct RecoverySecurityEpoch(pub u64); }
18. Monotonic.
19. Prevents rollback to unsafe historical state.
20. Hard Rule
A restore point older than the accepted security/deletion floor cannot be activated merely because it is cryptographically valid.
21. Backup Classes
#![allow(unused)] fn main() { pub enum BackupClass { Logical, Snapshot, Replica, Archive, RecoveryBundle, } }
22. Logical
Application-level state export.
23. Snapshot
Point-in-time storage image.
24. Replica
Continuously synchronized live copy.
25. Archive
Long-term cold retention.
26. RecoveryBundle
Explicit portable recovery artifact.
27. Hard Rule
Backup class determines restore semantics; they are not interchangeable.
28. Authoritative vs Rebuildable State
Classify all state.
29. State Classes
#![allow(unused)] fn main() { pub enum RecoveryStateClass { Authoritative, Rebuildable, Ephemeral, HardwareBound, Secret, } }
30. Authoritative
Must be recovered correctly.
Examples:
durable messages
tenant configuration
governance state
account lifecycle state
31. Rebuildable
Can be regenerated.
Examples:
indexes
caches
search projections
analytics rollups
32. Ephemeral
Should generally not restore.
Examples:
typing state
presence
temporary sessions
in-flight retries
33. HardwareBound
Cannot be blindly cloned.
Examples:
TPM-bound identity
secure-enclave keys
device-bound credentials
34. Secret
Needs separate custody.
Examples:
recovery secrets
root signing material
backup keys
35. Hard Rule
Restore logic is explicitly driven by state class.
36. Backup Manifest
#![allow(unused)] fn main() { pub struct BackupManifest { pub recovery_point: RecoveryPointId, pub domain: RecoveryDomain, pub schema_version: BackupSchemaVersion, pub security_epoch: RecoverySecurityEpoch, pub objects: Vec<BackupObjectRef>, pub deletion_floor: DeletionBarrierVersion, } }
37. Backup Object Ref
#![allow(unused)] fn main() { pub struct BackupObjectRef { pub object_id: BackupObjectId, pub state_class: RecoveryStateClass, pub digest: Digest, pub size: u64, } }
38. No Hidden Object Types
Hard rule.
39. Backup Encryption
All non-public backups encrypted.
40. Backup Encryption Key
Separate from runtime content keys.
41. Hard Rule
Compromise of backup infrastructure must not automatically expose production secrets.
42. Backup Key Hierarchy
Recommended:
Recovery Root
│
├── Account Backup Keys
├── Tenant Backup Keys
├── Service Backup Keys
└── Archive Keys
43. No Universal Backup Master Key
Hard rule.
44. Account Backup Keys
User-owned or threshold-recovery controlled.
45. Tenant Backup Keys
Organization-scoped.
46. Service Backup Keys
Environment/service-scoped.
47. Archive Keys
Separate lifecycle.
48. Key Rotation
Supported.
49. Backup Object Encryption
Envelope encryption.
50. Per-object or per-backup data key.
51. No one plaintext key shared across unrelated domains.
52. Hard rule.
53. Backup Integrity
Need more than encryption.
54. Integrity Controls
manifest signature
object digest
chunk digest
schema version
security epoch
deletion barrier
55. Backup Integrity State
#![allow(unused)] fn main() { pub enum BackupIntegrityState { Unknown, Validating, Valid, Invalid, Incomplete, } }
56. Unknown ≠ Valid
Hard rule.
57. Backup Verification
#![allow(unused)] fn main() { pub trait BackupVerifier { fn verify( &self, manifest: &BackupManifest, ) -> Result<VerifiedBackup, RecoveryError>; } }
58. Verify Before Recovery Catalog Admission
Hard rule.
59. Backup Signing
Service/authority specific.
60. Account backup may use user/recovery signer.
61. No central signing identity required.
62. Hard rule.
63. Chunked Backup
Large backups split into chunks.
64. Chunk Record
#![allow(unused)] fn main() { pub struct BackupChunk { pub index: u32, pub digest: Digest, pub encrypted_size: u64, } }
65. Resume and verify independently.
66. Full manifest digest still required.
67. Hard rule.
68. Incremental Backup
Supported.
69. Incremental Backup Chain
#![allow(unused)] fn main() { pub struct IncrementalBackup { pub base: RecoveryPointId, pub parent: Option<RecoveryPointId>, pub changes: Vec<BackupDeltaRef>, } }
70. Restore must verify full chain.
71. No missing-parent silent fallback.
72. Hard rule.
73. Backup Frequency
Based on RPO.
74. Recovery Point Objective
#![allow(unused)] fn main() { pub struct Rpo(pub Duration); }
75. Recovery Time Objective
#![allow(unused)] fn main() { pub struct Rto(pub Duration); }
76. Per service/domain.
77. No one global RPO/RTO.
78. Hard rule.
79. Example Classes
governance: low-frequency but high-assurance
messages: near-continuous durability
analytics: rebuildable
search index: rebuildable
80. Deletion Barrier
Critical.
81. Deleted accounts/content/keys must not reappear.
82. Deletion Barrier Version
#![allow(unused)] fn main() { pub struct DeletionBarrierVersion(pub u64); }
83. Restore Point Must Include Current Floor
84. Restore Rejects Older Barrier
Hard rule.
85. Deletion Barrier Contents
May include:
account deletion epochs
content deletion epochs
revocation epochs
tenant offboarding barriers
key destruction state
86. Hard Rule
Deletion protection state is authoritative recovery state.
87. Anti-Resurrection Ledger
#![allow(unused)] fn main() { pub struct AntiResurrectionLedger { pub version: DeletionBarrierVersion, pub entries: Vec<DeletionBarrierEntry>, } }
88. Applied Before restored data becomes active.
89. Hard rule.
90. Restore State Machine
#![allow(unused)] fn main() { pub enum RestoreState { Planned, Validating, Quiescing, Restoring, Reconciling, Verifying, Canary, Completed, Failed, RolledBack, } }
91. Planned
Recovery plan created.
92. Validating
Backup/keys/schema/policy checked.
93. Quiescing
Writes safely paused where required.
94. Restoring
Data/state loaded.
95. Reconciling
Reapply newer authoritative barriers/events.
96. Verifying
Control and integrity checks.
97. Canary
Limited service.
98. Completed
Trusted service resumed.
99. Hard Rule
Completed is impossible before verification.
100. Restore Plan
#![allow(unused)] fn main() { pub struct RestorePlan { pub recovery: RecoveryId, pub domain: RecoveryDomain, pub point: RecoveryPointId, pub target: RestoreTarget, pub required_checks: Vec<RecoveryCheck>, } }
101. Restore Target
#![allow(unused)] fn main() { pub enum RestoreTarget { ExistingEnvironment, CleanEnvironment, AlternateRegion, OfflineValidationEnvironment, } }
102. CleanEnvironment
Preferred after compromise.
103. Hard rule.
104. Restore Authorization
High-risk.
105. Restore Capability
#![allow(unused)] fn main() { pub struct RestoreCapability { pub recovery: RecoveryId, pub domain: RecoveryDomain, pub actions: BTreeSet<RecoveryAction>, pub expires_at: Timestamp, } }
106. Recovery Actions
#![allow(unused)] fn main() { pub enum RecoveryAction { ValidateBackup, Restore, Promote, Failover, Failback, ExportRecoveryEvidence, } }
107. Short-lived.
108. No permanent DR superuser.
109. Hard rule.
110. Multi-Party Approval
For critical domains:
governance
root keys
tenant-wide restore
regional failover
111. No unilateral irreversible restore.
112. Hard rule.
113. Restore Validation
Check:
manifest signatures
chunk digests
schema compatibility
security epoch
deletion floor
key availability
required migrations
114. No restore if any critical check unknown.
115. Hard rule.
116. Restore Into Clean Environment
Preferred for:
security incidents
regional compromise
supply-chain compromise
117. Rebuild infra from trusted artifacts first.
118. Then restore data.
119. Hard rule.
120. Disaster Recovery vs Incident Recovery
Part 96 incident recovery may invoke DR.
121. But DR also covers:
hardware loss
regional outage
database corruption
operator error
122. Separate workflows.
123. Hard rule.
124. Regional Failover
Move service to alternate region.
125. Region State
#![allow(unused)] fn main() { pub enum RegionState { Active, Standby, Degraded, Isolated, Failed, Recovering, } }
126. Active
Serving.
127. Standby
Ready.
128. Degraded
Partial capacity.
129. Isolated
Network/control-plane isolation.
130. Failed
Unavailable.
131. Recovering
Not yet trusted active.
132. No direct Failed→Active
Hard rule.
133. Failover Decision
Inputs:
availability
data freshness
security posture
privacy posture
capacity
federation state
134. No availability-only failover.
135. Hard rule.
136. Regional Failover Plan
#![allow(unused)] fn main() { pub struct RegionalFailoverPlan { pub source: RegionId, pub target: RegionId, pub required_replication_lag: Duration, pub required_controls: Vec<ControlId>, pub privacy_requirements: PrivacyFailoverPolicy, } }
137. Privacy Failover Policy
#![allow(unused)] fn main() { pub struct PrivacyFailoverPolicy { pub require_e2ee: bool, pub forbid_direct_fallback: bool, pub data_residency: Option<ResidencyConstraint>, } }
138. Hard Rule
Failover cannot weaken privacy/anonymity floor.
139. If compliant alternate region unavailable
service may remain unavailable/degraded.
140. No silent privacy downgrade.
141. Hard rule.
142. Data Residency
Some tenants/services may restrict region.
143. Failover must respect.
144. No cross-jurisdiction move without policy.
145. Hard rule.
146. Active/Passive
Simpler.
147. Active/Active
More complex.
148. Need conflict strategy.
149. No assumption all workloads support active/active.
150. Hard rule.
151. Database Failover
Depends on authoritative database.
152. PostgreSQL example:
replica promotion
fencing old primary
verify replication state
promote new primary
153. Fencing
Critical.
154. No split-brain.
155. Hard rule.
156. Fencing Token
#![allow(unused)] fn main() { pub struct FencingEpoch(pub u64); }
157. New primary gets higher epoch.
158. Old primary cannot resume writes.
159. Hard rule.
160. Quorum State Recovery
Part 76.
161. Never reduce quorum just to regain availability.
162. Hard rule.
163. Object Storage Recovery
Replicated/multi-region.
164. Private blobs encrypted.
165. Region failover doesn't require decrypting provider-side.
166. Hard rule.
167. Queue Recovery
Durable queue/outbox state.
168. Must avoid duplicate side effects.
169. Idempotency keys preserved.
170. Hard rule.
171. Event Stream Recovery
Replay from durable offset.
172. No replay before deletion/revocation filters.
173. Hard rule.
174. Cache Recovery
Rebuild.
175. Do not restore stale cache unless justified.
176. Hard rule.
177. Search Index Recovery
Rebuild from authoritative data + deletion ledger.
178. No stale backup restore.
179. Hard rule.
180. Analytics Recovery
Aggregate state may restore.
181. Raw telemetry not required.
182. No resurrection of expired analytics.
183. Hard rule.
184. Audit Recovery
Part 94.
185. Preserve:
chain heads
recovery epochs
retention state
186. No silent chain splice.
187. Hard rule.
188. Compliance Recovery
Part 95.
189. Exceptions/controls retain expiry.
190. No restored expired exception.
191. Hard rule.
192. SOC Recovery
Part 97.
193. Threat intel TTL/revocations preserved.
194. No expired IoC resurrection.
195. Hard rule.
196. Update System Recovery
Part 99.
197. Preserve:
security epoch
release revocations
trusted root
198. No rollback to revoked release.
199. Hard rule.
200. Backup Catalog
Tracks usable recovery points.
201. Recovery Catalog Entry
#![allow(unused)] fn main() { pub struct RecoveryCatalogEntry { pub point: RecoveryPointId, pub domain: RecoveryDomain, pub integrity: BackupIntegrityState, pub retention: RecoveryRetentionClass, pub tested: RestoreTestState, } }
202. Restore Test State
#![allow(unused)] fn main() { pub enum RestoreTestState { NeverTested, Passed, Failed, Stale, } }
203. NeverTested Backup
Not trusted as sole DR basis.
204. Hard rule.
205. Restore Testing
Mandatory.
206. Test Types
#![allow(unused)] fn main() { pub enum RestoreTestType { ManifestVerification, PartialRestore, FullServiceRestore, RegionalFailoverExercise, } }
207. Restore Drill
Runs in isolated environment.
208. No production impact.
209. Hard rule.
210. Full Restore Drill
At defined cadence.
211. Measures:
actual RPO
actual RTO
integrity
migration compatibility
operator readiness
212. No purely theoretical RTO.
213. Hard rule.
214. Disaster Exercises
Part 70.
215. Exercise scenarios:
region loss
database corruption
object-store outage
key loss
operator error
supply-chain compromise
216. Include privacy failure scenario.
217. Hard rule.
218. Continuity Modes
#![allow(unused)] fn main() { pub enum ContinuityMode { Normal, DegradedReadWrite, ReadOnly, OfflineLocalOnly, QueuedWrite, EmergencyMinimal, } }
219. Normal
Full service.
220. DegradedReadWrite
Reduced features.
221. ReadOnly
No new authoritative writes.
222. OfflineLocalOnly
Clients operate locally.
223. QueuedWrite
Writes accepted locally/outbox pending.
224. EmergencyMinimal
Critical features only.
225. Hard Rule
Continuity mode must be explicit and truthful.
226. No UI pretending normal service when degraded.
227. Feature Degradation Policy
Priorities:
security
identity
messaging core
emergency communication
control plane
bulk/background
228. Lower-priority features shed first.
229. Never disable encryption/anonymity to preserve convenience.
230. Hard rule.
231. Read-Only Mode
Useful during uncertainty.
232. Allows:
read existing state
export
diagnostics
233. Blocks:
unsafe writes
new trust changes
234. Hard rule.
235. Offline Local-First Continuity
Clients continue:
local messages
drafts
local search
nearby/local P2P
where architecture supports.
236. Server outage shouldn't destroy local functionality.
237. Good.
238. Queued Writes
Persist locally/outbox.
239. On recovery:
reauthorize
revalidate
deduplicate
240. No blind replay.
241. Hard rule.
242. Mailbox Continuity
Encrypted mailbox replicas.
243. Distinct provider identities.
244. Failover mailbox provider without changing account identity.
245. No plaintext copy.
246. Hard rule.
247. Anonymous Routing Continuity
If one mixnet path fails:
alternate anonymity-compliant route
248. If none available:
queue/fail
249. No silent direct fallback.
250. Hard rule.
251. Federation Continuity
Peer outage isolated.
252. Local domain still functions.
253. Pending federation events queue.
254. No transitive failover trust.
255. Hard rule.
256. DNS/Service Discovery Continuity
Use multiple signed/bootstrap paths.
257. Cache bounded signed endpoint records.
258. No insecure hardcoded fallback.
259. Hard rule.
260. Control Plane Recovery
Critical.
261. Recovery order:
identity/trust
secrets
config
service discovery
data plane
background services
262. No data-plane activation before trust plane.
263. Hard rule.
264. Secret Recovery
Part 80.
265. Restore references/metadata, not plaintext secrets if possible.
266. Reissue dynamic credentials.
267. Hard rule.
268. Root Key Disaster
Separate ceremony.
269. Threshold recovery/offline backup.
270. No one operator can restore root alone.
271. Hard rule.
272. Backup Key Loss
Need recovery options.
273. Account backup:
user recovery key
threshold shares
existing device
274. Tenant backup:
org recovery custodians
HSM escrow
275. No global decrypt-all recovery key.
276. Hard rule.
277. Key Escrow
Only narrowly for managed/org recovery where policy explicitly permits.
278. Not personal E2EE universal escrow.
279. Hard rule.
280. Recovery Key Rotation
If compromise suspected.
281. Re-encrypt future backup manifests/keys.
282. Old backups may need rewrap or retire.
283. Hard rule.
284. Cryptographic Erasure
Deletion can rely on key destruction.
285. Restore must honor destroyed-key state.
286. No restoring deleted key from archival backup.
287. Hard rule.
288. Restore Provenance
Every restored object records source point.
289. Recovery Provenance
#![allow(unused)] fn main() { pub struct RecoveryProvenance { pub recovery: RecoveryId, pub point: RecoveryPointId, pub restored_by: RecoveryAuthorityRef, pub target: RestoreTarget, } }
290. Scoped/admin identity only.
291. No user surveillance linkage.
292. Hard rule.
293. Recovery Evidence
Need signed proof of recovery operations.
294. Recovery Receipt
#![allow(unused)] fn main() { pub struct RecoveryReceipt { pub recovery: RecoveryId, pub domain: RecoveryDomain, pub point: RecoveryPointId, pub result: RecoveryResult, pub verification_digest: Digest, pub signature: SignatureBytes, } }
295. Recovery Result
#![allow(unused)] fn main() { pub enum RecoveryResult { Succeeded, Failed, RolledBack, } }
296. No success receipt before verification.
297. Hard rule.
298. Recovery Verification
Checks:
data integrity
control posture
key validity
revocation state
deletion barriers
schema compatibility
service health
299. Hard Rule
Recovery success is multidimensional, not "process exited 0."
300. Recovery Gate
#![allow(unused)] fn main() { pub struct RecoveryVerificationGate { pub required_controls: Vec<ControlId>, pub required_integrity_checks: Vec<IntegrityCheck>, pub required_privacy_checks: Vec<PrivacyCheck>, } }
301. Unknown check
blocks completion.
302. Hard rule.
303. Recovery Canary
Limited traffic/users/service shard.
304. Select by infrastructure shard, not user identity where possible.
305. Hard rule.
306. Failback
Return from alternate region.
307. Failback is separate operation.
308. Must verify:
source region clean
replication current
fencing safe
security posture pass
309. No automatic reverse switch.
310. Hard rule.
311. Failback State Machine
#![allow(unused)] fn main() { pub enum FailbackState { Planned, Syncing, Validating, Draining, Switching, Verifying, Completed, Failed, } }
312. Old active region fenced.
313. Hard rule.
314. Split-Brain Prevention
Use:
fencing epoch
quorum
leases
315. No dual-authoritative writer.
316. Hard rule.
317. Data Reconciliation
If divergent writes somehow occur.
318. Never naive LWW for critical domains.
319. Domain-specific reconciliation.
320. Hard rule.
321. Financial/Accounting Data
Requires strict consistency.
322. School/ERP-like data similarly may require deterministic conflict resolution.
323. User messaging may use event ordering/idempotency.
324. Recovery policy per domain.
325. Hard rule.
326. Backup Storage Providers
Provider-neutral.
327. Possible:
S3-compatible
object storage
offline archive
user local file
managed enterprise storage
328. Encryption before provider.
329. Provider never trusted with plaintext.
330. Hard rule.
331. Multi-Provider Backup
For critical domains.
332. Independent failure domains.
333. Do not assume two regions same provider = independent enough.
334. Hard rule.
335. Backup Replication Policy
#![allow(unused)] fn main() { pub struct BackupReplicationPolicy { pub minimum_copies: u8, pub independent_failure_domains: u8, pub geographic_separation: bool, } }
336. Per domain.
337. No unnecessary geographic replication of sensitive tenant data.
338. Hard rule.
339. Data Residency
Backup locations respect.
340. Archive locations explicit.
341. Hard rule.
342. Backup Retention
Class-based.
343. Example:
#![allow(unused)] fn main() { pub enum RecoveryRetentionClass { Short, Standard, Extended, LegalScoped, UserControlled, } }
344. No indefinite default.
345. Hard rule.
346. Retention Rotation
Example:
hourly
daily
weekly
monthly
347. Old backups deleted/crypto-erased.
348. Deletion ledger maintained.
349. Hard rule.
350. Backup Garbage Collection
Reference aware.
351. Incremental chains protected until dependents expire.
352. No orphan leak.
353. Hard rule.
354. Archive Restore
Slow path.
355. Must verify old schema compatibility.
356. No direct production activation.
357. Hard rule.
358. Long-Term Format Migration
Backups may outlive software version.
359. Need migration path.
360. Migration occurs in isolated environment.
361. Original backup preserved until new format verified.
362. Hard rule.
363. Client Backup Restore
Fresh device identity.
364. Do not restore:
old transport sessions
ratchet live state
push tokens
device-bound keys
365. Hard rule.
366. Client Logical Restore
Restore:
history
settings
contacts metadata
content
according to policy.
367. Re-establish security sessions fresh.
368. Hard rule.
369. Device Replacement
New DeviceId.
370. Old DeviceId not cloned.
371. Hard rule.
372. Messaging Session Restore
No blind ratchet restore.
373. Fresh session establishment.
374. Old pending messages dedup via MessageId.
375. Hard rule.
376. Contact/Relationship Restore
Logical relation restored if valid.
377. Revoked relationships remain revoked.
378. Hard rule.
379. Account Recovery
Part 57.
380. Recovery epoch prevents old devices/credentials returning.
381. Hard rule.
382. Tenant Restore
Need tenant-wide deletion/offboarding barriers.
383. Tenant A restore cannot affect B.
384. Hard rule.
385. Tenant Key Restore
Separate key domain.
386. No one tenant backup key can decrypt another.
387. Hard rule.
388. Managed Offboarding State
Preserved.
389. No restored removed employee access.
390. Hard rule.
391. Federation Restore
Restore:
peer agreements
trust roots
capabilities
revocations
392. No remote user data.
393. Peer trust revalidation required.
394. Hard rule.
395. Governance Restore
Highest assurance.
396. Multi-party.
397. Restore offline-signed policy history.
398. No downgrade to old permissive governance state.
399. Hard rule.
400. Disaster Recovery Access
Capability-controlled.
401. Roles:
#![allow(unused)] fn main() { pub enum RecoveryRole { RecoveryOperator, RecoveryApprover, SecurityReviewer, PrivacyReviewer, ServiceOwner, } }
402. Separation of duties.
403. No shared DR account.
404. Hard rule.
405. Emergency Access
Break-glass if required.
406. Short-lived.
407. Scope-specific.
408. Audited.
409. Cannot disable cryptographic/privacy floor.
410. Hard rule.
411. Restore Audit
Part 94.
412. Audit:
restore planned
restore approved
restore started
failover executed
recovery completed
failback completed
413. Not every object read.
414. Hard rule.
415. Compliance Integration
Part 95.
416. Controls:
backup freshness
restore test success
anti-rollback state
RPO/RTO compliance
deletion barrier preservation
417. No "backup exists" = pass.
418. Hard rule.
419. Incident Integration
Part 96.
420. Security incident restore into clean environment.
421. Recovery gate before service returns.
422. Hard rule.
423. SOC Integration
Part 97.
424. Recovery can consume active IoCs/revocations.
425. No expired threat intel restored.
426. Hard rule.
427. Vulnerability Integration
Part 98.
428. Restored artifact must not be blocked/vulnerable release.
429. Hard rule.
430. Update Integration
Part 99.
431. Recovery uses currently trusted release chain/security epoch.
432. Old backup cannot restore updater trust to weaker state.
433. Hard rule.
434. Supply-Chain Integration
Part 73.
435. Rebuild infra from exact signed artifacts.
436. No package installation from stale backup image blindly.
437. Hard rule.
438. Host Attestation Integration
Part 71.
439. Recovered hosts attested before service.
440. Hard rule.
441. Secrets Integration
Part 80.
442. Reissue dynamic credentials after restore.
443. No restore of expired access token cache.
444. Hard rule.
445. Database Integration
Part 74.
446. Use transactional restore/migrations.
447. Verify constraints/indexes/outbox/inbox.
448. Hard rule.
449. Event Bus Integration
Part 75.
450. Replay durable events safely.
451. Idempotency preserved.
452. No duplicate external side effects.
453. Hard rule.
454. Consensus Integration
Part 76.
455. Recover consensus metadata carefully.
456. Prefer fresh cluster membership with restored authoritative state if needed.
457. No cloning stale leader lease.
458. Hard rule.
459. Service Discovery Integration
Part 77.
460. Recovered endpoint not published before health/security validation.
461. Hard rule.
462. Edge Integration
Part 78.
463. Traffic shifted only after recovery gate.
464. Hard rule.
465. East-West Integration
Part 79.
466. New workload identities issued.
467. No cloned mTLS credentials from snapshot.
468. Hard rule.
469. Observability
Safe metrics:
backup freshness
restore duration
recovery success rate
replication lag
RPO/RTO attainment
470. Forbidden:
user-level recovery history
private content volume by identity
471. Hard rule.
472. DR SLOs
Examples:
verified backup freshness
regional failover time
restore validation time
deletion-barrier verification
473. Security SLO
0 restore below security epoch
0 revoked credential restored active
0 split-brain primary
474. Privacy SLO
0 privacy downgrade during failover
0 cross-tenant restore leakage
0 deleted state resurrection
475. Failure Modes
corrupt backup
missing key
stale replica
regional outage
failed failback
restore migration error
476. Corrupt Backup
Try earlier verified recovery point.
477. Do not promote invalid point.
478. Hard rule.
479. Missing Key
Use approved recovery path.
480. No bypass encryption.
481. Hard rule.
482. Stale Replica
Compare replication lag/RPO.
483. If too stale, degrade or require reconciliation.
484. No false zero-loss claim.
485. Hard rule.
486. Regional Outage
Fail over only if target meets control/privacy/data-residency gates.
487. Hard rule.
488. Failed Failback
Remain on current trusted region.
489. No forced reversal.
490. Hard rule.
491. Migration Error
Restore stays non-active.
492. Fix/migrate in isolation.
493. Hard rule.
494. Recovery Testing
Need dedicated resilience testkit.
495. Test Scenarios
corrupt backup
region loss
stale replica
deleted account restore
security epoch rollback
496. Integrity Test
Modified chunk detected.
497. Missing Chunk Test
Incomplete backup rejected.
498. Deletion Barrier Test
Deleted content/account cannot return.
499. Security Epoch Test
Old recovery point cannot reduce security floor.
500. Revoked Credential Test
Restored credential remains revoked.
501. Device Restore Test
Fresh DeviceId created.
502. Messaging Session Test
Old live ratchet/session not restored.
503. Tenant Test
Tenant A restore does not affect B.
504. Regional Failover Test
Privacy policy preserved.
505. Residency Test
Forbidden region rejected.
506. Fencing Test
Old primary cannot resume writes.
507. Queue Replay Test
No duplicate side effect.
508. Audit Chain Test
Recovery epoch/discontinuity preserved.
509. Threat Intel Test
Expired IoCs not restored active.
510. Update Test
Revoked release not restored.
511. Restore Drill Test
RPO/RTO measured against reality.
512. Backup Key Loss Test
Approved recovery path only.
513. Failback Test
No dual active primary.
514. Fuzzing
Fuzz:
backup manifest
incremental chain
restore plan
recovery receipt
failover state
515. Property Tests
Properties:
restore point below deletion/security floor can never reach Completed
failed critical verification can never promote recovery target
old fenced primary can never regain write authority
restored hardware-bound credential can never become active on a different device without re-provisioning
516. Formal Verification Targets
Strong candidates:
restore state machine
deletion anti-resurrection
regional failover/fencing
failback
517. Kani Candidate
recovery state transition and floor invariants.
518. TLA+ Candidate
active region → failure → failover → recovery → failback.
519. Loom Candidate
concurrent failover + stale writer + fencing epoch update.
520. Performance
Backup creation mostly background.
521. Continuous replication optimized separately.
522. Restore throughput high but verification remains mandatory.
523. No skipping integrity checks for speed.
524. Hard rule.
525. Backup Bandwidth
Incremental/chunked.
526. Dedup only where privacy permits.
527. No cross-user sensitive dedup strict mode.
528. Hard rule.
529. Compression
Before encryption.
530. Bound decompression.
531. No zip-bomb restore.
532. Hard rule.
533. Recovery Parallelism
Can restore independent objects in parallel.
534. Dependency ordering preserved.
535. Example:
schema
→ authoritative data
→ derived state
→ service activation
536. Hard rule.
537. Recovery Catalog Query
#![allow(unused)] fn main() { pub trait RecoveryCatalog { fn list( &self, domain: RecoveryDomain, ) -> Result<Vec<RecoveryCatalogEntry>, RecoveryError>; } }
538. Scoped.
539. No global list of every tenant/account backup to ordinary operators.
540. Hard rule.
541. Backup Service
#![allow(unused)] fn main() { pub trait BackupService { fn create( &self, domain: RecoveryDomain, ) -> Result<RecoveryPointId, RecoveryError>; fn verify( &self, point: RecoveryPointId, ) -> Result<BackupIntegrityState, RecoveryError>; } }
542. Restore Service
#![allow(unused)] fn main() { pub trait RestoreService { fn plan( &self, point: RecoveryPointId, target: RestoreTarget, ) -> Result<RestorePlan, RecoveryError>; fn execute( &self, capability: RestoreCapability, plan: RestorePlan, ) -> Result<RecoveryReceipt, RecoveryError>; } }
543. Failover Service
#![allow(unused)] fn main() { pub trait RegionalFailoverService { fn failover( &self, plan: RegionalFailoverPlan, ) -> Result<FailoverReceipt, RecoveryError>; fn failback( &self, plan: FailbackPlan, ) -> Result<FailoverReceipt, RecoveryError>; } }
544. Recovery Error Taxonomy
#![allow(unused)] fn main() { pub enum RecoveryError { RecoveryPointNotFound, BackupInvalid, BackupIncomplete, KeyUnavailable, SchemaIncompatible, SecurityEpochRollback, DeletionBarrierRollback, ResidencyViolation, PrivacyPolicyViolation, FencingFailure, VerificationFailed, RestoreDenied, FailoverDenied, Internal, } }
545. Storage
Separate:
backup manifests
encrypted backup objects
recovery catalog
deletion ledger
restore plans
recovery receipts
546. No one unencrypted recovery warehouse.
547. Hard rule.
548. Partitioning
By recovery domain and tenant/service scope.
549. No global user identity key.
550. Hard rule.
551. Crate Layout
Recommended:
crates/
├── siar-recovery-core/
├── siar-backup-manifest/
├── siar-backup-crypto/
├── siar-backup-integrity/
├── siar-recovery-catalog/
├── siar-restore-orchestrator/
├── siar-deletion-barrier/
├── siar-regional-failover/
├── siar-continuity-mode/
├── siar-recovery-verification/
├── siar-recovery-observability/
└── siar-recovery-testkit/
552. siar-recovery-core
Owns:
RecoveryId
RecoveryPointId
domains
states
errors
553. siar-backup-manifest
Canonical manifests/object references/schema versions.
554. siar-backup-crypto
Envelope encryption/key wrapping/recovery keys.
555. siar-backup-integrity
Digest/signature/chunk verification.
556. siar-recovery-catalog
Recovery point metadata/test status.
557. siar-restore-orchestrator
Plan/quiesce/restore/reconcile/verify/promote.
558. siar-deletion-barrier
Deletion/revocation anti-resurrection floor.
559. siar-regional-failover
fencing/failover/failback.
560. siar-continuity-mode
Normal/degraded/read-only/local-only/queued modes.
561. siar-recovery-verification
Post-restore control/privacy/integrity gates.
562. siar-recovery-observability
RPO/RTO/backup/restore health only.
563. siar-recovery-testkit
corruption/failover/deletion/rollback/tenant tests.
564. Security, Privacy & Correctness Invariants
Mandatory:
1. Backup, snapshot, replica, archive, and recovery bundle are distinct recovery classes with explicit semantics and are never treated as interchangeable.
2. Every restore point is bound to a schema version, cryptographic manifest, security epoch, and deletion barrier; stale-but-valid backups cannot roll the system back below current security/privacy floors.
3. Deleted accounts, content, credentials, relationships, keys, and tenant memberships cannot be resurrected by backup restore, replication lag, stale replica promotion, or old archive import.
4. Hardware-bound, ephemeral, and live session/ratchet state is never blindly cloned across devices or environments; fresh identities/credentials/sessions are established where required.
5. Regional failover and degraded operation preserve encryption, anonymity, authorization, residency, and tenant-isolation guarantees; unavailable compliant capacity causes queue/degradation rather than silent privacy downgrade.
6. Recovery authority is scoped, short-lived, auditable, and separated by recovery domain; there is no permanent disaster-recovery superuser or universal backup decryption key.
7. Recovery completion requires explicit integrity, security, privacy, schema, revocation, and control validation; service availability alone can never prove successful recovery.
8. Fencing epochs/quorum rules prevent split-brain and ensure an old primary cannot regain write authority after failover.
9. Backup encryption keys, runtime keys, tenant keys, account keys, and governance/root keys remain distinct and have separate custody/recovery processes.
10. RPO/RTO claims are validated by restore drills and regional-failover exercises, not inferred from the mere existence of backups or replicas.
11. Recovery data, metrics, and evidence remain scope-minimized and cannot become a centralized user-content archive, cross-tenant warehouse, or surveillance dataset.
12. Disaster recovery integrates with incident response, compliance, audit, update/release security, vulnerability management, host attestation, and federation while preserving all anti-rollback and privacy guarantees.
565. Initial Production Scope
Implement first:
typed recovery domains/classes
canonical backup manifests
envelope encryption
chunked/incremental backup
backup integrity verifier
security/deletion epochs
anti-resurrection ledger
restore state machine
clean-environment restore
recovery catalog
restore test status
RPO/RTO policy
regional active/passive failover
fencing epochs
continuity modes
tenant-scoped restore
client logical restore with fresh device/session identity
recovery receipts
compliance/audit integration
privacy-safe DR metrics
recovery testkit
Then add:
multi-provider backup policies
active/active region support
advanced mailbox/federation continuity
automated recovery rehearsal
independent recovery verification
formal failover/fencing/anti-resurrection verification
566. Definition of Done
Part 100 is complete when:
- backups are cryptographically verifiable and scope-separated
- recovery state classes are explicit
- recovery points carry security/deletion floors
- deleted/revoked state cannot reappear
- hardware/session identities are not cloned blindly
- restore orchestration has validate/quiesce/restore/reconcile/verify/canary stages
- regional failover is fenced and privacy-aware
- continuity modes are truthful
- failback is separately verified
- recovery keys have narrow custody
- tenant/account/service recovery domains remain isolated
- RPO/RTO are proven by exercises
- recovery completion requires security/privacy/control verification
- corruption/failover/deletion/rollback/fuzz/formal tests are specified
567. Final Architecture
PRODUCTION STATE
│
▼
BACKUP / REPLICATION
│
▼
INTEGRITY VERIFY
│
▼
RECOVERY CATALOG
│
┌──────────┼──────────┐
│ │ │
RESTORE FAILOVER OFFLINE DRILL
│ │ │
└──────────┼──────────┘
▼
RECONCILIATION
│
▼
SECURITY/PRIVACY GATE
│
▼
CANARY
│
▼
TRUSTED SERVICE
Resilience safety model:
encrypted backups
+
verified manifests
+
security/deletion epochs
+
scoped restore authority
+
regional fencing
+
privacy-preserving failover
+
restore drills
+
post-recovery verification
not:
copy everything everywhere, promote whichever replica is available, and hope old deleted or vulnerable state does not come back
568. Final Principle
Disaster recovery should restore trusted capability, not merely old data.
The correct model is:
back up selectively
+
encrypt independently
+
verify continuously
+
restore into trusted environments
+
preserve deletion/security floors
+
fail over without privacy downgrade
+
fence old writers
+
prove recovery through drills and controls
This architecture gives SIAR a privacy-preserving resilience foundation for backups, restore orchestration, tenant/account/service recovery, regional failover, failback, offline continuity, recovery drills, anti-resurrection, and recovery assurance while preserving the anonymity, local-first, least-authority, and anti-surveillance guarantees established across Parts 34–99.