Ceph also supports the ability to run two or more RADOS Gateway Zones to provide high availability of the S3 and swift-compatible storage across multiple sites. Each zone is backed by a completely separate Ceph cluster, meaning that it is extremely unlikely that any hardware of software failure can take the service completely offline. When using RGW in a multisite configuration, it's important to note that data is eventually consistent, so that data is not guaranteed to be in the same state in every zone immediately after it has been written.
For more information on RGW multi-site configurations, please consult the official Ceph documentation.