updated-learn-section

Author: rao-shwe

modules/learn/pages/services-and-indexes/services/services.adoc

@@ -17,6 +17,7 @@ Services intended to support a heavy workload can be deployed across multiple cl
 In Couchbase Server Version 7.6 and later, you can add one or more arbiter nodes to your cluster.
 include::learn:partial$arbiter-node-benefits.adoc[]
 
+
 == Services and Multi-Dimensional Scaling
 
 Couchbase Server provides the following services:
@@ -52,6 +53,27 @@ _Query Service_ depends on the _Index Service_ and on the _Data Service_).
 When the first node in a cluster is initialized, the services assigned to it become the default assignment for each other node subsequently to be added to the cluster.
 However, this default can be departed from, node by node, with one or more services omitted from the default, and one or more added.
 
+In Couchbase Server 8.0 and later versions, you can add or remove services on-demand on existing nodes in a cluster, without adding or removing nodes.
+
+* Index Service is represented by *index*.
+* Query Service is represented by *n1ql*.
+* Search Service is represented by *fts*.
+* Analytics Service is represented by *cbas*.
+* Eventing Service is represented by *eventing*.
+* Backup Service is represented by *backup*.
+
+Then a rebalance operation is automatically triggered to evenly distribute the service workload across the nodes.
+For information about adding or removing services on a node, see xref:manage:manage-nodes/modify-services-and-rebalance.adoc[Modify Services and Rebalance].
+
+NOTE: Adding or removing the Data Service from a node is not supported. Data Service is represented by *kv*.
+
+You can change the services running on nodes to support Multi-Dimensional Scaling (MDS).
+This flexibility lets you adjust your cluster as your needs evolve.
+
+For example, you may start with a small cluster where some nodes run multiple services, such as Index and Search, because you have more need for services than available nodes.
+As your needs grow, you can add nodes and move services to those new nodes to free resources on the original nodes.
+If a service becomes resource-constrained, you can add it to more nodes in the cluster to increase its capacity and meet demand.
+
 When first allocated to a node, a service requires the assignment of a specific memory quota, which becomes standard for that service in each of its instances across the cluster.
 (The exceptions to this are the Query and Backup Services, which never require a memory quota.)