. See Figure 15.If you have slow or unreliable WAN links or your directory has so many objects that the server is overwhelmed and access is slow, you should consider partitioning the directory. For a complete discussion of partitions, see Managing Partitions and Replicas.
Partitioning allows you to take part of the directory off one server and put it on another server.
A partition is a logical division of the NDS database. A directory partition forms a distinct unit of data in the tree that stores directory information.
Each directory partition consists of a set of container objects, all the objects contained in them, and data about those objects. NDS partitions don't include any information about the file system or the directories and files contained there.
Partitioning is done with ConsoleOne. Partitions are identified in ConsoleOne by the following partition icon: . See Figure 15.
Figure 15 
In the example, the partition icon is next to the Tree object. This means it is the top-most container in the partition. No partitions are shown by any other containers, so this partition is the only one.
This is the default partitioning for NDS, keeping the entire directory together in one partition.
Notice in the example that Server1 is selected. When you select a server in ConsoleOne and display the Partition and Replica view, any replicas held on that server are shown on the right. In this case, Server1 holds a replica of the only partition. See Replicas.
Partitions are named by their top-most container. In Figure 16 there are two partitions, named Tree and Finance. YourCo is called a child partition of Tree, since it was split off from the Tree. Tree is called the parent partition of Finance.
Figure 16 
You might create such a partition because the directory has so many objects that the server is overwhelmed and access to NDS is slow. Creating the new partition allows you to split the database and pass the objects in that branch to a different server.
In the preceding example, suppose that Server1 holds replicas of both the Tree partition and the Finance partition. At this point, you haven't gained any performance advantage from NDS since Server1 still holds the entire directory (replicas of both partitions).
To gain the desired performance advantage, you need to move one of the replicas to a different server. For instance, if you move the Tree partition to Server2, then Server2 holds all objects in the Tree and YourCo containers. Server1 only holds objects in the Finance and Accounts containers. The load on both Server1 and Server2 is less than it would be with no partitioning.
Suppose your network spans two sites, a North site and a South Site, separated by a WAN link. Three servers are at each site. See Figure 17.
Figure 17 
NDS performs faster and more reliably in this scenario if the directory is divided in two partitions.
With a single partition, the replicas are either kept at one site or distributed between the two sites. This proves unwieldy for two reasons:
The two-partition solution shown below solves performance and reliability problems over the WAN link. See Figure 18.
Figure 18 
Replicas of the Tree partition are kept on servers at the North site. Replicas of the South partition are kept on servers at the South site, as shown in Figure 19.
Figure 19 
For each site, the objects that represent local resources are kept locally. Synchronization traffic among servers also happens locally over the LAN, rather than over the slow, unreliable WAN link.
NDS traffic is generated over the WAN link, however, when a user or administrator accesses objects at a different site.