Self-Healing Infrastructure

Multi-Signal Health Consensus

No single metric determines node health. VectorScaleDB evaluates multiple independent signals and reaches consensus before declaring a node unhealthy — eliminating false positives from transient issues.

Signals

Independent health dimensions

Each node is evaluated across multiple independent dimensions: heartbeat latency, data integrity verification, query response quality, storage consistency, federation protocol compliance, and resource utilization. A slow heartbeat alone does not trigger repair — it must correlate with other signals.

Consensus

Weighted signal aggregation

Health signals are aggregated with configurable weights. Critical signals (data integrity, storage consistency) carry higher weight than performance signals (query latency, heartbeat). A node with corrupted data is flagged immediately; a node with high latency gets a grace period.

Peer Validation

Cross-node health verification

Before any repair action, neighboring nodes independently verify the health assessment. A node that appears unhealthy to one peer but healthy to three others is not repaired — the reporting peer is investigated instead. This prevents network-level misdiagnosis.

Staged Repair Pipeline

Repair is not binary. VectorScaleDB applies the minimum intervention needed, escalating through stages only when simpler repairs fail.

Stage 1

Local self-correction

The node attempts to repair itself using local resources. Corrupted index entries are rebuilt from stored segments. Inconsistent caches are flushed and repopulated. Storage integrity checks identify and quarantine damaged regions. Most issues resolve at this stage without any network involvement.

Index rebuild from durable segment data
Cache flush and reconstruction
Storage region quarantine and repair
Automatic checkpoint rollback if needed

Stage 2

Network-assisted recovery

If local repair fails, the node requests recovery assistance from federation peers. Missing or corrupted segments are reconstructed from replicas on other nodes. The node's behavioral history is verified against the network's collective memory. Data that cannot be recovered locally is fetched from the network.

Segment reconstruction from federation replicas
Behavioral history verification against peers
Incremental sync of missing data ranges
Content-hash verification of every recovered object

Authenticated Repair

Repair operations are cryptographically authenticated at every step. A compromised node cannot exploit the repair process to inject malicious data into the network.

Identity

Signed repair requests

Every repair request is signed with the node's Ed25519 key. Peer nodes verify the signature and the requester's trust score before providing recovery data. Low-trust nodes receive limited assistance; quarantined nodes receive none.

Verification

Content-hash validation

Every recovered data object is verified against its content hash before acceptance. Data from peer nodes that does not match the expected hash is rejected and the peer is flagged for investigation. No unverified data enters the repaired node.

Audit

Full repair audit trail

Every repair action — detection, diagnosis, each repair stage, verification, and re-entry — is recorded in the audit chain. Post-incident analysis can reconstruct the exact sequence of events, root cause, and remediation steps taken.

Automatic Reintegration

After repair completes, the node must prove its health before resuming full participation. Re-entry is graduated, not instantaneous.

Verification

Post-repair integrity check

Before re-entering the network, the repaired node runs a comprehensive integrity verification: storage consistency, index correctness, encryption key validity, and federation protocol compliance. All checks must pass. A single failure sends the node back to the repair pipeline.

Graduated Re-Entry

Progressive trust restoration

A repaired node does not immediately resume full participation. It enters a probation period where it handles read-only queries and limited ingestion. As it demonstrates consistent healthy behavior, its responsibilities are gradually restored. Full participation resumes only after sustained stability.

Graduated Re-Entry Protocol

Trust is restored incrementally. Each stage requires demonstrated stability before the next level of responsibility is granted.

Phase 1

Observer mode

The node rejoins the gossip protocol and receives updates but does not serve queries or accept ingestion. It synchronizes its state with the network and verifies consistency. Duration: configurable, typically 5-15 minutes.

Phase 2

Read-only participation

The node begins serving read queries at reduced priority. Query results are spot-checked against peer responses for correctness. Any discrepancy extends the probation period. Duration: proportional to the severity of the original failure.

Phase 3

Full restoration

After sustained healthy operation through Phases 1 and 2, the node resumes full responsibilities: ingestion, queries, federation, and — if applicable — backbone consensus participation. Trust score recovery begins from this point.