Active Directory Lightweight Directory Services (AD LDS) stores directory data in a hierarchical, file-based directory store. By default, the directory store for a given AD LDS instance is located in the following file:

%ProgramFiles%\Microsoft ADAM\instancename\data\adamntds.dit

Each AD LDS instance has a separate directory store. Any data operation that you perform in AD LDS, including searches, reads, imports, exports, indexing, replication, backups, and restores, uses the AD LDS directory store in some way. The directory store is organized into logical directory partitions, also called naming contexts.


Like Active Directory Domain Services (AD DS), AD LDS uses the Extensible Storage Engine (ESE) to manage its directory store.

Directory partitions

The AD LDS directory store is organized into logical directory partitions. There are three different types of directory partitions: configuration, schema, and application. Each AD LDS directory store must contain a single configuration directory partition and a single schema directory partition, and it can contain zero or more application directory partitions. The following table summarizes these partition types, their contents, and AD LDS requirements.

Partition type Distinguished name Required/optional Contents




AD LDS configuration information




Class and attribute definitions


Assigned during partition creation


Application data

Configuration directory partition

The configuration directory partition holds information about AD LDS replication scheduling and replica sets, information that defines the other partitions in the replication set, information about the users and groups in the replica set, and other information.

Schema directory partition

The schema directory partition holds the definitions for the type of data that can be held by the directory store. The AD LDS directory service relies on the definitions in the schema partition for maintaining data consistency. In addition, applications can refer to the schema partition to determine the type of data that the AD LDS instance allows. You can extend the schema to allow AD LDS to hold data that is specific to a particular application. For more information about AD LDS schemas, see Understanding the AD LDS Schema.


A common configuration partition and a common schema partition are replicated to AD LDS service instances that belong to the same configuration set. For more information about replication, see Understanding AD LDS Replication and Configuration Sets.

Application directory partitions

Application directory partitions hold the data that is used by your applications. You can create an application partition during AD LDS setup or anytime after installation. Depending on your application, you might extend the schema manually or your application might automatically extend the schema for you. Typically, you manage data in a given application directory partition through your application. After the application directory partition is created, AD LDS holds the application partition reference objects in CN=Partitions,CN=Configuration.

Additional references