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Shrink index

The shrink index API operation moves all of your data in an existing index into a new index with fewer primary shards.


POST /my-old-index/_shrink/my-new-index
  "settings": {
    "index.number_of_replicas": 4,
    "index.number_of_shards": 3
    "new-index-alias": {}

Path and HTTP methods

POST /<index-name>/_shrink/<target-index>

When creating new indices with this operation, remember that OpenSearch indices have the following naming restrictions:

  • All letters must be lowercase.
  • Index names can’t begin with underscores (_) or hyphens (-).
  • Index names can’t contain spaces, commas, or the following characters:

    :, ", *, +, /, \, |, ?, #, >, or <

URL parameters

The shrink index API operation requires you to specify both the source index and the target index. All other parameters are optional.

Parameter Type description
<index-name> String The index to shrink.
<target-index> String The target index to shrink the source index into.
wait_for_active_shards String Specifies the number of active shards that must be available before OpenSearch processes the request. Default is 1 (only the primary shard). Set to all or a positive integer. Values greater than 1 require replicas. For example, if you specify a value of 3, the index must have two replicas distributed across two additional nodes for the request to succeed.
master_timeout Time How long to wait for a connection to the master node. Default is 30s.
timeout Time How long to wait for the request to return a response. Default is 30s.

Request body

You can use the request body to configure some index settings for the target index. All fields are optional.

Field Type Description
alias Object Sets an alias for the target index. Can have the fields filter, index_routing, is_hidden, is_write_index, routing, and search_routing. See index aliases.
settings Object Index settings you can apply to your target index. See index settings.
max_primary_shard_size Bytes Sets the maximum size of a primary shard in the target index. For example, if this field is set to 100 GB, and the source index’s primary shards total to 300 GB, then the target index has 3 primary shards of 100 GB each.