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 +13,49 @@ 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.
 
-TBD
+==== File-Based Rebalance (FBR)
+[.edition]#{enterprise}#
+
+Couchbase Server Enterprise Edition {totoro} introduces File-Based Rebalance (FBR) for the Data Service.
+FBR accelerates cluster rebalance by copying vBucket storage files between nodes rather than streaming individual documents using Database Change Protocol (DCP) replication.
+It 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}:
+
+* *Enabled by default*: FBR is enabled by default for Couchbase Server Enterprise Edition, both for self-managed deployments and Couchbase Capella.
+If you choose to, you can turn it off globally using the new `dataServiceFileBasedRebalanceEnabled` setting.
+You can also override the global setting for specific buckets using the new `dataServiceRebalanceType` setting when creating or editing buckets.
+
+* *Automatic rebalance type selection*: Couchbase Server automatically determines if it can use FBR to move a vBucket.
+If it cannot, it automatically falls back to copying the vBucket using DCP.
+
+* *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.
+
+* *Data transfer rate throttle*: The new `snapshot_download_throttle_bytes` setting lets you limit FBR's data transfer rate between nodes.
+Setting this value too high (or setting it to 0, which makes those transfers unlimited) can increase the latency of KV operations.
+
+NOTE: FBR is a Couchbase Server Enterprise Edition feature.
+Couchbase Server Community Edition continues to use DCP-based rebalance for all vBucket moves.
+
+For more information, see xref:learn:clusters-and-availability/rebalance.adoc#file-based-rebalance[File-Based Rebalance].
 
 
 === 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 +64,25 @@ 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.