Force mergeedit

Phases allowed: hot, warm.

Force merges the index into the specified maximum number of segments.

This action makes the index read-only.

To use the forcemerge action in the hot phase, the rollover action must be present. If no rollover action is configured, ILM will reject the policy.


(Required, integer) Number of segments to merge to. To fully merge the index, set to 1.

(Optional, string) Use the best_compression codec. Valid values: best_compression.

Setting "codec": "best_compression" in the ILM forcemerge action causes {ilm-int} to close and then re-open the index prior to the force merge. During this time, the index is unavailable for both read and write operations.


PUT _ilm/policy/my_policy
  "policy": {
    "phases": {
      "warm": {
        "actions": {
          "forcemerge" : {
            "max_num_segments": 1