Merge 'docs: add documentation for automatic repair' from Botond Dénes

Explain what automatic repair is and how to configure it. While at it, improve the existing repair documentation a bit.

Fixes: SCYLLADB-130

This PR missed the 2026.1 branch date, so it needs backport to 2026.1, where the auto repair feature debuts.

Closes scylladb/scylladb#28199

* github.com:scylladb/scylladb:
  docs: add feature page for automatic repair
  docs: inter-link incremental-repair and repair documents
  docs: incremental-repair: fix curl example

docs/features/automatic-repair.rst

@@ -0,0 +1,23 @@
+.. _automatic-repair:
+
+Automatic Repair
+================
+
+Traditionally, launching `repairs </operating-scylla/procedures/maintenance/repair>`_ in a ScyllaDB cluster is left to an external process, typically done via `Scylla Manager <https://manager.docs.scylladb.com/stable/repair/index.html>`_.
+
+Automatic repair offers built-in scheduling in ScyllaDB itself. If the time since the last repair is greater than the configured repair interval, ScyllaDB will start a repair for the tablet `tablet </architecture/tablets>`_ automatically.
+Repairs are spread over time and among nodes and shards, to avoid load spikes or any adverse effects on user workloads.
+
+To enable automatic repair, add this to the configuration (``scylla.yaml``):
+
+.. code-block:: yaml
+
+    auto_repair_enabled_default: true
+    auto_repair_threshold_default_in_seconds: 86400
+
+This will enable automatic repair for all tables with a repair period of 1 day. This configuration has to be set on each node, to an identical value.
+More featureful configuration methods will be implemented in the future.
+
+To disable, set ``auto_repair_enabled_default: false``.
+
+Automatic repair relies on `Incremental Repair </features/incremental-repair>`_ and as such it only works with `tablet </architecture/tablets>`_ tables.

docs/features/incremental-repair.rst

@@ -3,7 +3,7 @@
 Incremental Repair
 ==================
 
-ScyllaDB's standard repair process scans and processes all the data on a node, regardless of whether it has changed since the last repair. This operation can be resource-intensive and time-consuming. The Incremental Repair feature provides a much more efficient and lightweight alternative for maintaining data consistency.
+ScyllaDB's standard `repair </operating-scylla/procedures/maintenance/repair>`_ process scans and processes all the data on a node, regardless of whether it has changed since the last repair. This operation can be resource-intensive and time-consuming. The Incremental Repair feature provides a much more efficient and lightweight alternative for maintaining data consistency.
 
 The core idea of incremental repair is to repair only the data that has been written or changed since the last repair was run. It intelligently skips data that has already been verified, dramatically reducing the time, I/O, and CPU resources required for the repair operation.
 
@@ -37,7 +37,12 @@ The available modes are:
 *   ``disabled``: Completely disables the incremental repair logic for the current operation. The repair behaves like a classic, non-incremental repair, and it does not read or update any incremental repair status markers.
 
 
-The incremental_mode parameter can be specified using nodetool cluster repair, e.g., nodetool cluster repair --incremental-mode incremental. It can also be specified with the REST API, e.g., curl -X POST "http://127.0.0.1:10000/storage_service/tablets/repair?ks=ks1&table=tb1&tokens=all&incremental_mode=incremental"
+The incremental_mode parameter can be specified using nodetool cluster repair, e.g., nodetool cluster repair --incremental-mode incremental.
+It can also be specified with the REST API, e.g.:
+
+.. code::
+
+    curl -X POST "http://127.0.0.1:10000/storage_service/tablets/repair?ks=ks1&table=tb1&tokens=all&incremental_mode=incremental"
 
 Benefits of Incremental Repair
 ------------------------------
@@ -46,6 +51,8 @@ Benefits of Incremental Repair
 *   **Reduced Resource Usage:** Consumes significantly less CPU, I/O, and network bandwidth compared to a full repair.
 *   **More Frequent Repairs:** The efficiency of incremental repair allows you to run it more frequently, ensuring a higher level of data consistency across your cluster at all times.
 
+Tables using Incremental Repair can schedule repairs in ScyllaDB itself, with `Automatic Repair </features/automatic-repair>`_.
+
 Notes
 -----
 

docs/features/index.rst

@@ -17,6 +17,7 @@ This document highlights ScyllaDB's key data modeling features.
    Workload Prioritization </features/workload-prioritization>
    Backup and Restore </features/backup-and-restore>
    Incremental Repair </features/incremental-repair/>
+   Automatic Repair </features/automatic-repair/>
    Vector Search </features/vector-search/>
 
 .. panel-box::
@@ -44,5 +45,7 @@ This document highlights ScyllaDB's key data modeling features.
   * :doc:`Incremental Repair </features/incremental-repair/>` provides a much more
     efficient and lightweight approach to maintaining data consistency by
     repairing only the data that has changed since the last repair.
+  * :doc:`Automatic Repair </features/automatic-repair/>` schedules and runs repairs
+    directly in ScyllaDB, without external schedulers.
   * :doc:`Vector Search in ScyllaDB </features/vector-search/>` enables
     similarity-based queries on vector embeddings.

docs/operating-scylla/procedures/maintenance/repair.rst

@@ -58,4 +58,12 @@ See also
 
 * `Blog: ScyllaDB Open Source 3.1: Efficiently Maintaining Consistency with Row-Level Repair <https://www.scylladb.com/2019/08/13/scylla-open-source-3-1-efficiently-maintaining-consistency-with-row-level-repair/>`_
 
+Incremental Repair
+------------------
 
+Built on top of `Row-level Repair <row-level-repair_>`_ and `Tablets </architecture/tablets>`_, Incremental Repair enables frequent and quick repairs. For more details, see `Incremental Repair </features/incremental-repair>`_.
+
+Automatic Repair
+----------------
+
+Built on top of `Incremental Repair </features/incremental-repair>`_, `Automatic Repair </features/automatic-repair>`_ offers repair scheduling and execution directly in ScyllaDB, without external processes.