Replication overview

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QuestDB Enterprise provides primary-replica replication for high availability and disaster recovery. Your data is automatically synced to replica instances via an object store, with no direct network connections required between nodes.

Why use replication?

• High availability - Replicas can take over if the primary fails
• Read scaling - Distribute query load across multiple replicas
• Disaster recovery - Restore from any point in time using stored WAL files
• Geographic distribution - Place replicas closer to users in different regions
• Zero performance impact - Replicas don't affect primary performance

How it works

The primary instance writes data to a Write Ahead Log (WAL) and uploads these files to an object store (AWS S3, Azure Blob Storage, GCS, or NFS). Replica instances download and apply these files to stay in sync.

graph TD
    primary[Primary]
    objectStore[Object Store]
    replica1[Replica 1]
    replica2[Replica 2]
    replicaN[Replica ..N]

    primary --> objectStore
    objectStore --> replica1
    objectStore --> replica2
    objectStore --> replicaN

This decoupled architecture means:

• Add or remove replicas without touching the primary
• Replicas can be in different regions or availability zones
• Object store provides durability and point-in-time recovery

Availability strategies

Hot availability - Run replicas continuously alongside the primary for instant failover. Faster recovery, higher cost.

Cold availability - Reconstruct a new primary from the latest snapshot and WAL files when needed. Slower recovery, lower cost.

Supported object stores

Need something else? Contact us.

Requirements

Replication works with WAL-enabled tables - tables that have a designated timestamp and are partitioned. This covers most time-series use cases.

Tables without timestamps (typically used for reference/lookup data) are not replicated automatically and should be populated separately on each instance.

Bring Your Own Cloud (BYOC)

QuestDB Enterprise can be self-managed or operated by QuestDB's team under the BYOC model.

With BYOC, QuestDB handles operations of all primary and replica instances on your infrastructure. Managed infrastructure uses standard cloud provider tools (CloudFormation for AWS, Lighthouse for Azure) and is fully owned and auditable by you.

Next steps

Ready to set up replication? Continue to the Setup Guide.