DOC-12491 xdcrDiffer in Server build

modules/ROOT/nav.adoc

@@ -141,6 +141,7 @@ include::third-party:partial$nav.adoc[]
  ** xref:manage:manage-xdcr/replicate-using-scopes-and-collections.adoc[Replicate Using Scopes and Collections]
  ** xref:manage:manage-xdcr/filter-xdcr-replication.adoc[Filter a Replication]
  ** xref:manage:manage-xdcr/recover-data-with-xdcr.adoc[Recover Data with XDCR]
+ ** xref:manage:manage-xdcr/xdcr-differ.adoc[xdcrDiffer Utility]
 * xref:manage:manage-security/security-management-overview.adoc[Manage Security]
  ** xref:manage:manage-security/manage-security-settings.adoc[Manage Security Settings]
  ** xref:manage:manage-security/manage-users-and-roles.adoc[Manage Users, Groups, and Roles]

modules/introduction/partials/new-features-80.adoc

@@ -117,8 +117,15 @@ Additional information sent by clients at connection time can be found in the lo
 
 [#section-new-feature-800-XDCR]
 === XDCR
-https://jira.issues.couchbase.com/browse/MB-61048[MB-61048]::
-Once faulty remote cluster credentials are fixed, XDCR will now be able to more quickly restart replications that depend on the repaired references.
+
+https://jira.issues.couchbase.com/browse/MB-62564[MB-62564]::
+
+`xdcrDiffer` is a diagnostic utility included in the Couchbase Server package.
+This utility verifies data consistency between XDCR clusters.
+It identifies missing or mismatched documents by comparing metadata and content hashes across source and target clusters.
++
+For more information, see xref:manage:pages/manage-xdcr/xdcr-differ.adoc[xdcrDiffer Utility].
+
 
 [#section-new-feature-800-query-service]
 === Query Service

modules/manage/pages/manage-xdcr/xdcr-differ.adoc

@@ -0,0 +1,68 @@
+= xdcrDiffer Utility
+:description: pass:q[The `xdcrDiffer` utility helps you verify data consistency between XDCR clusters by comparing document metadata and values, and reporting missing or mismatched documents.]
+
+[abstract]
+{description}
+
+`xdcrDiffer` is a diagnostic utility included in the Server installation package for convenient access.
+Previously, you'd build this utility from source using the xdcrDiffer GitHub repository.
+
+== What is xdcrDiffer?
+
+`xdcrDiffer` is a Diff tool that helps you check data consistency between XDCR clusters.
+For full usage instructions and Q&A, see the https://github.com/couchbase/xdcrDiffer?tab=readme-ov-file#readme[xdcrDiffer ReadMe].
+
+The output report from `xdcrDiffer` provides information such as:
+
+* A list of document IDs missing from the target cluster.
+
+* A list of documents with mismatched data.
+
+== Utility Files
+
+The utility includes these files:
+
+* `xdcrDiffer` (binary)
+
+* `runDiffer.sh` (shell script)
+
+To run the utility, use the `runDiffer.sh` script.
+
+TIP: Run the xdcrDiffer utility on a cluster node that does not serve Data service, as the utility can consume significant resources.
+You can also run it on an arbiter node, which does not run any services.
+
+== How the xdcrDiffer Utility Works
+
+`xdcrDiffer` acts as a DCP consumer and creates DCP streams from the Data nodes.
+Then it reads data from both the source and target clusters, and stores results in the directory you specify as `outputDir`.
+
+**Before you begin:**
+
+Estimate the required storage for utility output.
+Make sure the specified `outputDir` has enough space for collecting data.
+
+Each mutation from DCP is stored with its metadata.
+Each mutation typically uses about 102 bytes and the key size.
+Calculate the storage needed as follows:
+
+----
+Storage needed = (102 bytes + key size) × number of documents in the source and target buckets being replicated
+----
+
+NOTE: Ensure you check the details of usage, limitations, and information about how to read the output reports in https://github.com/couchbase/xdcrDiffer?tab=readme-ov-file#readme[xdcrDiffer ReadMe].
+
+The following is an example of running `xdcrDiffer.sh` with an option to compare both metadata and body during the report generation portion of the utility run.
+
+----
+runDiffer.sh --username=Administrator --password=password --hostname=localhost:8091 --sourceBucket=travel-sample --targetBucket=travel-sample --remoteClusterName=cluster2 --compareType=both --outputDir=/has_enough_space/xdcr_differ_outputdir
+----
+
+== Comparison Process
+
+* `xdcrDiffer` collects each document's metadata and generates a SHA-512 digest of its value.
+
+* After capturing all data from both clusters, `xdcrDiffer` compares documents by using either document ID or key.
+
+** If a document is missing in either cluster, the utility reports the missing document.
+
+** If all documents are present, the utility compares metadata and the body hash to verify if they match.