store limit v2: add more experimental description (#19553) (#19583)

configure-store-limit.md

@@ -69,6 +69,10 @@ store limit 1 5 remove-peer         // store 1 can at most delete 5 peers per mi
 
 ### Principles of store limit v2
 
+> **Warning:**
+> 
+> Store limit v2 is an experimental feature. It is not recommended that you use it in the production environment. This feature might be changed or removed without prior notice. If you find a bug, you can report an [issue](https://github.com/pingcap/tidb/issues) on GitHub.
+
 When [`store-limit-version`](/pd-configuration-file.md#store-limit-version-new-in-v710) is set to `v2`, store limit v2 takes effect. In v2 mode, the limit of operators are dynamically adjusted based on the capability of TiKV snapshots. When TiKV has fewer pending tasks, PD increases its scheduling tasks. Otherwise, PD reduces the scheduling tasks for the node. Therefore, you do not need to manually set `store limit` to speed up the scheduling process.
 
 In v2 mode, the execution speed of TiKV becomes the main bottleneck during migration. You can check whether the current scheduling speed has reached the upper limit through the **TiKV Details** > **Snapshot** > **Snapshot Speed** panel. To increase or decrease the scheduling speed of a node, you can adjust the TiKV snapshot limit ([`snap-io-max-bytes-per-sec`](/tikv-configuration-file.md#snap-io-max-bytes-per-sec)).

pd-control.md

@@ -332,7 +332,7 @@ Usage:
 
 - `store-limit-mode` is used to control the mode of limiting the store speed. The optional modes are `auto` and `manual`. In `auto` mode, the stores are automatically balanced according to the load (deprecated).
 
-- `store-limit-version` controls the version of the store limit formula. In v1 mode, you can manually modify the `store limit` to limit the scheduling speed of a single TiKV. The v2 mode is an experimental feature. In v2 mode, you do not need to manually set the `store limit` value, as PD dynamically adjusts it based on the capability of TiKV snapshots. For more details, refer to [Principles of store limit v2](/configure-store-limit.md#principles-of-store-limit-v2).
+- `store-limit-version` controls the version of the store limit formula. In v1 mode, you can manually modify the `store limit` to limit the scheduling speed of a single TiKV. The v2 mode is an experimental feature. It is not recommended that you use it in the production environment. In v2 mode, you do not need to manually set the `store limit` value, as PD dynamically adjusts it based on the capability of TiKV snapshots. For more details, refer to [Principles of store limit v2](/configure-store-limit.md#principles-of-store-limit-v2).
 
     ```bash
     config set store-limit-version v2       // using store limit v2

releases/release-7.1.0.md

@@ -386,7 +386,7 @@ Compared with the previous LTS 6.5.0, 7.1.0 not only includes new features, impr
 
 + PD
 
-    - Add a controller that automatically adjusts the size of the store limit based on the execution details of the snapshot. To enable this controller, set `store-limit-version` to `v2`. Once enabled, you do not need to manually adjust the `store limit` configuration to control the speed of scaling in or scaling out [#6147](https://github.com/tikv/pd/issues/6147) @[bufferflies](https://github.com/bufferflies)
+    - Add a controller that automatically adjusts the size of the store limit based on the execution details of the snapshot. To enable this controller, set `store-limit-version` to `v2` (experimental). Once enabled, you do not need to manually adjust the `store limit` configuration to control the speed of scaling in or scaling out [#6147](https://github.com/tikv/pd/issues/6147) @[bufferflies](https://github.com/bufferflies)
     - Add historical load information to avoid frequent scheduling of Regions with unstable loads by the hotspot scheduler when the storage engine is raft-kv2 [#6297](https://github.com/tikv/pd/issues/6297) @[bufferflies](https://github.com/bufferflies)
     - Add a leader health check mechanism. When the PD server where the etcd leader is located cannot be elected as the leader, PD actively switches the etcd leader to ensure that the PD leader is available [#6403](https://github.com/tikv/pd/issues/6403) @[nolouch](https://github.com/nolouch)