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Split index

The split index API operation splits an existing read-only index into a new index, cutting each primary shard into some amount of primary shards in the new index.


PUT /sample-index1/_split/split-index1
  "settings": {
    "index": {
      "number_of_shards": 4,
      "number_of_replicas": 2
  "aliases": {
    "sample-alias1": {}

Path and HTTP methods

POST /<source-index>/_split/<target-index>
PUT /<source-index>/_split/<target-index>

Index naming restrictions

OpenSearch indexes 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

Your request must include the source and target indexes. All split index parameters are optional.

Parameter Type Description
<source-index> String The source index to split.
<target-index> String The index to create.
wait_for_active_shards String 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 operation 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. Default is 30s.

Request body

The split index API operation creates a new target index, so you can specify any index settings and aliases to apply to the target index.


    "acknowledged": true,
    "shards_acknowledged": true,
    "index": "split-index1"
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