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Back Up Cluster Metadata

This procedure shuts down the mongod instance of a config server in order to create a backup of a sharded cluster’s metadata. The cluster’s config servers store all of the cluster’s metadata, most importantly the mapping from chunks to shards.

When you perform this procedure, the cluster remains operational [1].

  1. Disable the cluster balancer process temporarily. See Disable the Balancer for more information.
  2. Shut down one of the config databases.
  3. Create a full copy of the data files (i.e. the path specified by the dbPath option for the config instance.)
  4. Restart the original configuration server.
  5. Re-enable the balancer to allow the cluster to resume normal balancing operations. See the Disable the Balancer section for more information on managing the balancer process.
[1]While one of the three config servers is unavailable, the cluster cannot split any chunks nor can it migrate chunks between shards. Your application will be able to write data to the cluster. See Config Servers for more information.