TechNote 2015001: Combining Swarm Clusters

Document Identifier:TechNote 2015001
Document Date:April 15, 2015
Software Package:SWARM
Version:Swarm 7 or later


This technical note provides instructions for combining multiple Swarm clusters.

As data centers and disaster recovery strategies evolve, you might need to merge two separate Swarm clusters into a single cluster, combining all data from both clusters. To do this, you will select one cluster to go forward and merge the other cluster into it.

Requirements to merge clusters

  • All nodes in each cluster meet the minimum hardware requirements
  • Both clusters have the same network latency
  • Namespace must be distinct for all objects

Distinct namespace means that no domains or buckets can have the same name in both clusters (unless the domain or bucket originated in another cluster and migrated via intercluster replication). Resolve any domain name collisions before merging clusters, following the steps in the “Resolving Duplicate Domain Names in a Mirrored or DR Cluster” section of the Swarm Guide .

How to merge clusters

After ensuring that the namespace between the two clusters does not overlap, take the following steps to merge the clusters:

  1. Select which of the two clusters will keep its cluster name and multicast group address. For example, if cluster is the cluster to go forward, it keeps its current configuration and the merging cluster ( will be reconfigured to match.
  2. In the merging cluster (, update all configuration parameters to match the target cluster (
    1. Make sure that , , and security.administrators are updated to match exactly.
    2. If you have statically assigned your IP addresses, you may also need to reassign appropriate IP addresses for nodes in the merging cluster.
  3. In the merging cluster, if feeds are configured, delete them.
  4. In the merging cluster, reboot all nodes, either all at once or one at a time.
    Caution: To ensure persistence and the correct precedence for runtime settings, do not reboot all nodes in both clusters at once.
  5. If you deleted feeds in the merging cluster, restart the feeds in the target cluster: from the Feeds area of the Swarm Admin Console in the target cluster, edit each configured feed, select the Restart feed box, and Save .
  6. If you had to resolve namespace collisions prior to merging the clusters, monitor Admin Console errors for several days, watching for warnings related to colliding names.

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