Configure Independent Shard Scaling

Retrieve the independent shard scaling schema.

Make a request to the Atlas Administration API Return One Cluster from One Project endpoint. The request returns one replicationSpecs entry per shard.

Select a template schema.

From among the replicationSpecs, select one to which to match the other shards for symmetric scaling. Note the following properties from the chosen shard's regionConfigs:

• instanceSize for each shard role such as electableSpecs, readOnlySpecs, or analyticsSpecs.

• diskSizeGB, ebsVolumeType, and diskIOPS, or equivalent storage fields for the various cluster vendors.

To ensure continuity of performance, select your highest-tier shard as the template.

Compose a symmetric replicationSpecs array.

Using your chosen template schema as a basis, compose a PATCH request payload in which each shard's instanceSize values for electableSpecs and readOnlySpecs are identical.

{
  "replicationSpecs": [
    {
      "id": "SHARD_ID_0",
      "regionConfigs": [
        {
          "providerName": "AWS",
          "regionName": "US_EAST_1",
          "zoneName": "Zone1",
          "electableSpecs": {
            "instanceSize": "M60",
            "nodeCount": 3,
            "diskSizeGB": 2048,
            "ebsVolumeType": "PROVISIONED",
            "diskIOPS": 4000
          },
          "readOnlySpecs": {
            . . .
          },
          "analyticsSpecs": {
            . . .
          }
        }
      ]
    },
    {
      "id": "SHARD_ID_1",
      "regionConfigs": [
        . . .
      ]
    },
    . . .
  ]
}

You must preserve the id values of existing shards. Match the tier, storage, and disk settings for every shard.

Apply the PATCH.

Make a request to the Atlas Administration API Update One Cluster in One Project endpoint using the payload defined previously. This initiates a rolling resize of all shards in the cluster.