Chapter 7. Multiple Datacenters

You may deploy a Ceph cluster across geographic regions; however, this is NOT RECOMMENDED UNLESS you use a dedicated network connection between datacenters. Ceph prefers consistency and acknowledges writes synchronously. Using the internet (packet-switched with many hops) between geographically separate datacenters will introduce significant write latency.

You may specify multiple IP addresses and subnets for your public and cluster networks in your Ceph configuration file. For example:

public network {ip-address}/{netmask} [, {ip-address}/{netmask}]
cluster network {ip-address}/{netmask} [, {ip-address}/{netmask}]

public network {ip-address}/{netmask} [, {ip-address}/{netmask}]
cluster network {ip-address}/{netmask} [, {ip-address}/{netmask}]

Ensure that the IP addresses/subnets within the public network can reach each other, and the IP addresses/subnets within the cluster network can reach each other. We recommend keeping the cluster network separate from the public network and not connected to the internet to prevent DDOS attacks from crippling heartbeats, replication, backfilling and recovery.