Coveo High Availability, Multi-Region Topology, and Enterprise Disaster Recovery

1. The 99.99% Enterprise SLA Guarantee

A four-nines (99.99%) availability SLA permits no more than 4.38 minutes of unscheduled downtime per month across global search operations. Achieving this requires eliminating single points of failure (SPOFs) at every tier: DNS, network ingress, API gateway, compute pods, and physical storage shards.

2. Edge Topology: Anycast Routing & DDoS Protection

All incoming requests to *.coveo.com resolve via a globally distributed Anycast network powered by Cloudflare:

• Geo-Proximity Routing: User requests automatically terminate at the nearest edge point of presence (PoP) across 300+ cities worldwide, completing TLS handshakes at the edge to shave 40–80ms off connection latency.
• DDoS Mitigation: Layer 3/4 volumetric attacks and Layer 7 HTTP flood attacks are absorbed at the edge without reaching regional AWS application load balancers.
• Static Asset Caching: Headless JavaScript libraries, icons, and static search assets are served directly from edge cache with 99%+ cache hit ratios.

3. Multi-Zone Sharded Search Cluster Architecture

Behind the regional API gateways, Coveo deploys distributed search clusters across multiple AWS Availability Zones (AZs):

1. Shard Partitioning: Large indexes (e.g. 50M+ items) are partitioned into horizontal shards. A query is broadcast across shards in parallel, and partial result sets are merged using distributed priority queues.
2. Multi-AZ Active Replicas: Every shard has at least three active replicas spread across independent physical availability zones within the cloud region (e.g., us-east-1a, us-east-1b, us-east-1c).
3. Raft Consensus & Auto-Healing: Node heartbeats are monitored continuously. If a node fails or an entire AZ suffers a power disruption, the cluster controller instantly removes the failed replica from traffic routing in under 500ms.

4. Data Sovereignty & Regional Compliance (GDPR / HIPAA)

Global enterprises face strict legal requirements regarding where data is stored and processed:

• European Union (GDPR): Coveo provides dedicated European cloud organizations where document indexes, customer telemetry, and ML model training never leave AWS Frankfurt (eu-central-1) or AWS Ireland (eu-west-1).
• HIPAA / SOC2 Type II: Dedicated encryption at rest using AWS KMS Customer Managed Keys (CMK) with full audit trail logging via AWS CloudTrail.
• Index Air-Gapping: Multi-tenant isolation guarantees that documents and usage telemetry from Organization A can never be accessed or evaluated by Organization B.

5. Resiliency Patterns: Circuit Breakers & Graceful Degradation

What happens when an auxiliary service (such as an external CRM OAuth server or an intensive Machine Learning model) experiences latency spikes or network timeouts?

Coveo implements strict Circuit Breakers and fallback modes:

• ML Inference Fast-Fail: If the Automatic Relevance Tuning (ART) inference pod does not return ranking weights within 15ms, the query pipeline aborts the ML call and immediately serves high-speed lexical Lucene results. The user receives results in 25ms rather than waiting 3 seconds for a failing model.
• Stale Cache Fallback: If the real-time Usage Analytics ingestion buffer experiences backpressure, queries continue to serve using the last known good model snapshot.

6. Disaster Recovery: RPO & RTO Runbook