# Multi-Data center Multi-Data center (Multi-DC) replication enables you to have multiple copies of the data on multiple servers across more than one data center. Weaviate supports running a single cluster across multiple data centers (since `v1.31`), so you can place nodes in different geographic regions for lower latency and keep your data redundant across locations. Multi-DC replication is beneficial if you have user groups spread over different geographical locations (e.g. Iceland and Australia). When you place nodes in different local regions of user groups, latency can be decreased. Multi-DC replication also comes with the additional benefit that data is redundant on more physical locations, which means that in the rare case of an entire data center going down, data can still be served from another location. If all replica nodes are in the same data center, network requests between nodes are cheap and fast, but the whole deployment is at risk if that data center goes down. Spreading a cluster's nodes across data centers removes this single point of failure, so your data remains available even if an entire data center becomes unreachable. To run a cluster across data centers, tune Weaviate's inter-node networking for the higher-latency, lower-reliability links between regions. See [Running a single cluster across data centers (WAN)](#running-a-single-cluster-across-data-centers-wan) below. ![Replication multi-dc](/img/docs/replication-architecture/replication-regional-proximity-3.png) ## Running a single cluster across data centers (WAN) Weaviate can operate a single cluster across data centers (a wide-area network, or WAN) by adjusting its inter-node communication for high-latency, lower-reliability links. ### Enabling WAN mode Set the `CLUSTER_ADVERTISE_ADDR` environment variable to enable WAN mode. When it is set, Weaviate switches its internal [memberlist](https://github.com/hashicorp/memberlist) configuration to `DefaultWANConfig`, which increases timeouts and relaxes failure-detection thresholds so they are suitable for cross-data center communication. ### Key environment variables | Variable | Description | Required | | -------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------- | | `CLUSTER_ADVERTISE_ADDR` | The public IP address that other nodes should use to reach this node. Setting this enables WAN mode. Must be a valid IP address (hostnames are rejected). | Yes (for WAN) | | `CLUSTER_ADVERTISE_PORT` | The port to advertise to other nodes. If not set, it defaults to `CLUSTER_GOSSIP_BIND_PORT`. If set, it must be between `1024` and `65535`. | No | | `CLUSTER_BIND_ADDR` | The local address to bind to. Defaults to `0.0.0.0`. | No | | `CLUSTER_GOSSIP_BIND_PORT` | The port used for gossip (memberlist) traffic. Defaults to `7946`. | No | | `CLUSTER_DATA_BIND_PORT` | The port used for data traffic. Defaults to `CLUSTER_GOSSIP_BIND_PORT + 1`. | No | | `CLUSTER_JOIN` | A comma-separated list of `host:port` addresses of existing cluster members to join. | Yes (for joining) | ### Example configuration Below is an example environment configuration for a node intended to participate in a cross-data center cluster: ```yaml environment: - CLUSTER_HOSTNAME=weaviate-0 - CLUSTER_ADVERTISE_ADDR=203.0.113.10 # Public IP of this node - CLUSTER_JOIN=203.0.113.20:7946 # Public IP:Port of a node in another DC - CLUSTER_BIND_ADDR=0.0.0.0 # Optional; this is already the default bind address - CLUSTER_GOSSIP_BIND_PORT=7946 - CLUSTER_DATA_BIND_PORT=7947 - RAFT_BOOTSTRAP_EXPECT=3 # Use an odd number > 1 across DCs for faster, more reliable elections - RAFT_JOIN=203.0.113.20:8300 # Join an existing Raft voter (default Raft port is 8300) ``` ### Notes - **Latency**: Cross-data center operations inherently have higher latency. Make sure your application timeouts account for this. - **Security**: Gossip and data traffic are not encrypted by default. For cross-data center communication over the public internet, use a VPN or other secure tunnel, or make sure `CLUSTER_ADVERTISE_ADDR` is only reachable over a private network (for example, VPC peering). ## Questions and feedback Have a question or feedback? Here's how to reach us. ::::card-grid :::card{title="Community Forum" href="https://forum.weaviate.io/c/support" icon="messages-square"} Ask questions and connect with other developers on our **Community forum**. ::: :::card{title="Support" href="/guides/support-overview" icon="life-buoy"} Weaviate Cloud user or customer? Find the right channel on the **Support page**. ::: :::: ## Related pages - [Agents](./agents-index.md) - [AI-assisted Weaviate code generation](./ai-assisted-vibe-coding-index.md) - [APIs](./apis-index.md) - [Authorization and authentication](./authorization-and-authentication-index.md) - [Benchmarks](./benchmarks-index.md) - [Best practices](./best-practices-index.md) - [Client libraries](./clients-index.md) - [Client Libraries / SDKs](./client-libraries-index.md) - [Cloud](./cloud-index.md) - [Cloud account management](./cloud-account-management-index.md) # Agent Instructions This portal answers questions programmatically. To receive a synthesized, source-cited answer instead of crawling page by page, append the `?ask=` query parameter to any page URL on this site: /guides/quickstart?ask=how+do+I+authenticate Optional parameters: - `&goal=` steers the answer toward your objective (e.g. `&goal=write+a+python+client`). - `&version=