Merge pull request #341 from pingyu/release-6.5.1-6.6.0

Add release notes for v6.5.1 & v6.6.0

Author: pingyu

content/docs/6.5/new-features/overview.md

@@ -9,6 +9,16 @@ menu:
 
 This document lists some significant features and improvements since **TiKV 6.2**.
 
+## [TiKV 6.5.1](https://docs.pingcap.com/tidb/v6.5/release-6.5.1)
+
+### Key new features and improvements
+
+- Support starting TiKV on a CPU with less than 1 core [#13586](https://github.com/tikv/tikv/issues/13586) [#13752](https://github.com/tikv/tikv/issues/13752) [#14017](https://github.com/tikv/tikv/issues/14017) @[andreid-db](https://github.com/andreid-db)
+- Increase the thread limit of the Unified Read Pool (`readpool.unified.max-thread-count`) to 10 times the CPU quota, to better handle high-concurrency queries [#13690](https://github.com/tikv/tikv/issues/13690) @[v01dstar](https://github.com/v01dstar)
+- Change the the default value of `resolved-ts.advance-ts-interval` from `"1s"` to `"20s"`, to reduce cross-region traffic [#14100](https://github.com/tikv/tikv/issues/14100) @[overvenus](https://github.com/overvenus)
+
+
+
 ## [TiKV 6.5.0](https://docs.pingcap.com/tidb/v6.5/release-6.5.0)
 
 ### Key new features and improvements

content/docs/dev/new-features/overview.md

@@ -1,10 +1,44 @@
 ---
 title: What's New
-description: New features and improvements about TiKV under development
+description: New features and improvements about TiKV since 6.6
 menu:
     "dev":
         weight: 1
         identifier: What's New-dev
 ---
 
-This document lists some significant features and improvements about TiKV under development.
+This document lists some significant features and improvements since **TiKV 6.6**.
+
+## [TiKV 6.6.0](https://docs.pingcap.com/tidb/v6.6/release-6.6.0)
+
+### Key new features and improvements
+
+#### Scalability
+
+* Support Partitioned Raft KV storage engine (experimental) [#11515](https://github.com/tikv/tikv/issues/11515) [#12842](https://github.com/tikv/tikv/issues/12842) @[busyjay](https://github.com/busyjay) @[tonyxuqqi](https://github.com/tonyxuqqi) @[tabokie](https://github.com/tabokie) @[bufferflies](https://github.com/bufferflies) @[5kbpers](https://github.com/5kbpers) @[SpadeA-Tang](https://github.com/SpadeA-Tang) @[nolouch](https://github.com/nolouch)
+
+    Before TiDB v6.6.0, TiKV's Raft-based storage engine used a single RocksDB instance to store the data of all 'Regions' of the TiKV instance. To support larger clusters more stably, starting from TiDB v6.6.0, a new TiKV storage engine is introduced, which uses multiple RocksDB instances to store TiKV Region data, and the data of each Region is independently stored in a separate RocksDB instance. The new engine can better control the number and level of files in the RocksDB instance, achieve physical isolation of data operations between Regions, and support stably managing more data. You can see it as TiKV managing multiple RocksDB instances through partitioning, which is why the feature is named Partitioned-Raft-KV. The main advantage of this feature is better write performance, faster scaling, and larger volume of data supported with the same hardware. It can also support larger cluster scales.
+
+    Currently, this feature is experimental and not recommended for use in production environments.
+
+    For more information, see [documentation](https://docs.pingcap.com/tidb/v6.6/partitioned-raft-kv).
+
+#### DB operations
+
+* The TiKV-CDC tool is now GA and supports subscribing to data changes of RawKV [#48](https://github.com/tikv/migration/issues/48) @[zeminzhou](https://github.com/zeminzhou) @[haojinming](https://github.com/haojinming) @[pingyu](https://github.com/pingyu)
+
+    TiKV-CDC is a CDC (Change Data Capture) tool for TiKV clusters. TiKV and PD can constitute a KV database when used without TiDB, which is called RawKV. TiKV-CDC supports subscribing to data changes of RawKV and replicating them to a downstream TiKV cluster in real time, thus enabling cross-cluster replication of RawKV.
+
+    For more information, see [documentation](https://tikv.org/docs/latest/concepts/explore-tikv-features/cdc/cdc/).
+
+* Support configuring read-only storage nodes for resource-consuming tasks @[v01dstar](https://github.com/v01dstar)
+
+    In production environments, some read-only operations might consume a large number of resources regularly and affect the performance of the entire cluster, such as backups and large-scale data reading and analysis. TiDB v6.6.0 supports configuring read-only storage nodes for resource-consuming read-only tasks to reduce the impact on the online application. Currently, TiDB, TiSpark, and BR support reading data from read-only storage nodes. You can configure read-only storage nodes according to [steps](https://docs.pingcap.com/tidb/v6.6/readonly-nodes#procedures) and specify where data is read through the system variable `tidb_replica_read`, the TiSpark configuration item `spark.tispark.replica_read`, or the br command line argument `--replica-read-label`, to ensure the stability of cluster performance.
+
+    For more information, see [documentation](https://docs.pingcap.com/tidb/v6.6/readonly-nodes).
+
+* Support dynamically modifying `store-io-pool-size` [#13964](https://github.com/tikv/tikv/issues/13964) @[LykxSassinator](https://github.com/LykxSassinator)
+
+    The TiKV configuration item [`raftstore.store-io-pool-size`](https://docs.pingcap.com/tidb/v6.6/tikv-configuration-file#store-io-pool-size-new-in-v530) specifies the allowable number of threads that process Raft I/O tasks, which can be adjusted when tuning TiKV performance. Before v6.6.0, this configuration item cannot be modified dynamically. Starting from v6.6.0, you can modify this configuration without restarting the server, which means more flexible performance tuning.
+
+    For more information, see [documentation](https://docs.pingcap.com/tidb/v6.6/dynamic-config).