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Handle low disk space

OpenSearch® relies on the watermarks to respond to low disk space. Read more about each of them in the dedicated article.

When you're running low on disk space using Aiven for OpenSearch, you can take one of these actions:

  • Upgrade to a larger plan from with a help of Aiven console or by using Aiven CLI client.
  • Clean up unnecessary indices. Thus, for logs, it is often beneficial to create a separate, daily indices, allowing easy and efficient clean-up of the oldest data.

Follow-up actions after cleaning space

If low watermark or high watermark thresholds are exceeded, but data is eventually cleaned up, no further action is needed, as OpenSearch will continue allowing writes. However, if flood_state watermark is exceeded, you must manually unset read_only_allow_delete for each affected index. This can be done by updating index settings:

curl https://USER:PASSWORD@HOST:PORT/INDEX_NAME/_settings \
-X PUT \
-H 'Content-Type: application/json' \
-d '{"index.blocks.read_only_allow_delete": null}'

These are the placeholders you will need to replace in the code sample:

USERUser name to use when accessing the OpenSearch cluster
PASSWORDPassword to use when accessing the OpenSearch cluster
HOSTHost name for the connection
PORTPort number for the connection
INDEX_NAMEName of the index

This needs to be done separately for each index that was marked as read-only by OpenSearch.


Aiven does not automatically unset this option to ensure no flipping around read-only and read-write state.