DOC-13858 Server File-Based Rebalance for Data Service

modules/ROOT/nav.adoc

@@ -358,6 +358,7 @@ include::cli:partial$cbcli/nav.adoc[]
     **** xref:rest-api:rest-cluster-removenode.adoc[Removing Nodes from Clusters]
 
    *** xref:rest-api:rest-rebalance-overview.adoc[Rebalance]
+    **** xref:rest-api:file-based-data-rebalance.adoc[]
     **** xref:rest-api:rest-retrieve-cluster-rebalance-reason-codes.adoc[Getting Rebalance Reason Codes]
     **** xref:rest-api:rest-cluster-rebalance.adoc[Rebalancing the Cluster]
     **** xref:rest-api:rest-get-rebalance-progress.adoc[Getting Rebalance Progress]

modules/introduction/pages/whats-new.adoc

@@ -1,16 +1,17 @@
-= What's New in Version 8.1
+= What's New in Version {totoro}
 :description: Couchbase is the modern database for enterprise applications.
 :page-aliases: security:security-watsnew
+:totoro: codename Totoro release
 :page-toclevels: 2
 
 [abstract]
 {description} +
-Couchbase Server 8.1 combines the strengths of relational databases with the flexibility, performance, and scale of Couchbase.
+Couchbase Server {totoro} combines the strengths of relational databases with the flexibility, performance, and scale of Couchbase.
 
 For information about platform support changes, deprecation notifications, and fixed and known issues, see the xref:release-notes:relnotes.adoc[Release Notes].
 
 [#new-features-81]
-== New Features and Enhancements in 8.1.0
+== New Features and Enhancements in {totoro}
 
 This release introduces the following new features.
 

modules/introduction/partials/new-features-81.adoc

@@ -1,7 +1,7 @@
 [#section-new-feature-810-platform-support]
 === Platform Support
 
-Couchbase Server 8.1 adds support for the following operating systems:
+Couchbase Server {totoro} adds support for the following operating systems:
 
 * TBD
 
@@ -13,24 +13,48 @@ TBD
 
 === Data Service Changes
 
-Couchbase Server 8.1 introduces several new features for the Data Service.
+Couchbase Server {totoro} introduces several new features for the Data Service.
+
+==== File-Based Rebalance (FBR)
+
+Couchbase Server {totoro} introduces File-Based Rebalance (FBR) for the Data Service.
+FBR accelerates cluster rebalance by copying vBucket storage files directly between nodes rather than streaming data through the DCP (Database Change Protocol) replication pipeline.
+This eliminates the serialization and pipeline overhead of DCP backfill for large, disk-resident datasets.
+
+The following changes apply to the Data Service rebalance behavior in {totoro}:
+
+* *File-Based Rebalance*: FBR transfers vBucket data files directly from the source node to the destination node during the backfill phase of a vBucket move, bypassing the full DCP backfill mechanism used in prior releases.
+
+* *Enabled by default*: FBR is enabled by default for Enterprise Edition, both for self-managed deployments and Couchbase Capella.
+No configuration is required to activate it.
+
+* *Automatic rebalance type selection*: The server automatically determines whether FBR or DCP is more efficient for each vBucket move.
+When FBR is not applicable or not expected to be faster, the server falls back to DCP automatically.
+
+* *New bucket-level rebalance type setting*: A new per-bucket setting, `dataServiceRebalanceType`, allows operators to control rebalance behavior at the bucket level, overriding the cluster-level FBR setting.
+
+* *Separate vBucket move concurrency for FBR*: A new setting, `dataServiceFileBasedRebalanceMovesPerNode`, controls the maximum number of concurrent file-based vBucket moves per node.
+This is independent of the existing `rebalanceMovesPerNode` setting, which applies to DCP rebalance.
+
+NOTE: FBR is an Couchbase Server Enterprise Edition feature.
+Couchbase Server Community Edition continues to use DCP-based rebalance for all vBucket moves.
 
-TBD
 
+See xref:learn:clusters-and-availability/rebalance.adoc#file-based-rebalance[File-Based Rebalance] for more information. 
 
 === Non-Data Services
 
-Couchbase Server 8.1 release has key non-Data Services enhancements. 
+Couchbase Server {totoro} release has key non-Data Services enhancements. 
 
 
 === Couchbase Cluster
 
-Couchbase Server 8.1 release has added cluster enhancements and diagnostic capabilities.
+Couchbase Server {totoro} release has added cluster enhancements and diagnostic capabilities.
 
 [#unstable-metric]
 ==== New Metric to Detect Unstable Nodes
 
-Couchbase Server 8.1.0 introduces a new metric, `cm_node_unreachable_total`, to help you monitor for unstable nodes in your cluster.
+Couchbase Server {totoro} introduces a new metric, `cm_node_unreachable_total`, to help you monitor for unstable nodes in your cluster.
 An unstable node periodically becomes unavailable but recovers before the auto failover timeout expires.
 This metric counts the number of times a node has been unable to reach another node in the cluster.
 By monitoring it, you can identify nodes that are having issues before they become unavailable for long enough to be automatically failed over.
@@ -39,25 +63,25 @@ See xref:learn:clusters-and-availability/unstable-nodes.adoc[] for more informat
 
 === XDCR
 
-Couchbase Server 8.1 release has key cross datacenter replication (XDCR) enhancements and diagnostic capabilities. 
+Couchbase Server {totoro} release has key cross datacenter replication (XDCR) enhancements and diagnostic capabilities. 
 
 TBD.
 
 === Security and Authentication
 
-Couchbase Server 8.1 release has key security and authentication enhancements.
+Couchbase Server {totoro} release has key security and authentication enhancements.
 
 TBD.
 
 === Query Service
 
-Couchbase Server 8.1 release adds these Query Service features. 
+Couchbase Server {totoro} release adds these Query Service features. 
 
 
 TBD.
 
 === Search Service
 
-Couchbase Server 8.1 introduces several new features for the xref:search:search.adoc[Search Service].
+Couchbase Server {totoro} introduces several new features for the xref:search:search.adoc[Search Service].
 
 TBD.