S3 Multisite

Replication → S3 multisite shows the multisite realms of licensed croit clusters.

• Shards behind counts the replication log shards that still have changes to sync.
• i opens a site's details: sync states, data sync per source zone, endpoints. Times are UTC.
• Refresh reads the status right away; otherwise CDM reads it regularly. CDM does not replace real-time failover monitoring.

Line
green	in sync
amber	catching up
grey	a sync state is not reported
red, dashed	not replicating, or the site cannot be read

Setup

Set up multisite creates a realm; Add secondary adds a site to one. All clusters involved need write access.

1. Sites: a primary that serves S3, and secondaries that do not run S3 yet.
2. Primary: CDM converts the cluster into a multisite primary if it is not one yet.
3. Per secondary: zone name, gateway servers, optionally Read-only zone.
4. Review: CDM checks the clusters and whether the secondaries can reach the primary.

CDM derives the sync endpoints from the gateways. If the gateways sit behind NAT or a load balancer, untick Use the derived sync endpoints and enter your own.

The setup runs as tasks; Show log on the realm or History → Tasks shows their logs. If one secondary fails, the following ones are not set up.

Changing the primary

Open a secondary's details with i and choose Promote to primary. Needs write access.

Case	When	Result
Switch over	the primary is reachable	the old primary becomes a secondary
Fail over	the primary is unreachable	the chosen secondary becomes primary
Fail back	the old primary is back (Claims primary)	the old primary becomes primary again

The promotion restarts the new primary's S3 gateways.