Merge remote-tracking branch 'upstream/master' into update-sysvars-from-source

Author: morgo

pd-configuration-file.md

@@ -244,6 +244,16 @@ Configuration items related to scheduling
 + The number of Region scheduling tasks performed at the same time
 + Default value: `2048`
 
+### `hot-region-schedule-limit`
+
++ Controls the hot Region scheduling tasks that are running at the same time. It is independent of the Region scheduling.
++ Default value: `4`
+
+### `hot-region-cache-hits-threshold`
+
++ The threshold used to set the number of minutes required to identify a hot Region. PD can participate in the hotspot scheduling only after the Region is in the hotspot state for more than this number of minutes.
++ Default value: `3`
+
 ### `replica-schedule-limit`
 
 + The number of Replica scheduling tasks performed at the same time

tikv-configuration-file.md

@@ -300,6 +300,21 @@ Configuration items related to the sharing of block cache among multiple RocksDB
 + Default value: 45% of the size of total system memory
 + Unit: KB|MB|GB
 
+## storage.io-rate-limit
+
+Configuration items related to the I/O rate limiter.
+
+### `max-bytes-per-sec`
+
++ Limits the maximum I/O bytes that a server can write to or read from the disk (determined by the `mode` configuration item below) in one second. When this limit is reached, TiKV prefers throttling background operations over foreground ones. The value of this configuration item should be set to the disk's optimal I/O bandwidth, for example, the maximum I/O bandwidth specified by your cloud disk vendor. When this configuration value is set to zero, disk I/O operations are not limited.
++ Default value: `"0MB"`
+
+### `mode`
+
++ Determines which types of I/O operations are counted and restrained below the `max-bytes-per-sec` threshold. Currently, only the write-only mode is supported.
++ Optional value: `"write-only"`
++ Default value: `"write-only"`
+
 ## raftstore
 
 Configuration items related to Raftstore