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Reviewing Your eDirectory Tree Design

Novell Cool Solutions: Feature
By Linda Kennard

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Posted: 22 May 2003

Changes to your network or organization -- such as upgrades, departmental shifts, and company mergers -- might require changes to your tree design. Among other considerations, consider the following when reviewing your eDirectory tree design:

  • Tree type
  • Partition strategies
  • Replica placement

Tree Type

Generally speaking, there are two types of trees

  • Enterprise trees are used primarily for file and print requests for a single organization

  • eCommerce trees are used for file and print requests but also used for secure authentication to web-based applications either inside or outside your company's firewall
Tree Tips

Whether you implement an enterprise or eCommerce tree, these two tips apply:

  • Design your tree as a pyramid, with more objects and containers defined at the bottom layers of the tree than at the top layers of the tree.
  • Keep the [Root] container small to facilitate repairing and extending the eDirectory schema.

Tree Tops

The ideal design for the top portion of your tree just below the [Root] and Organization containers depends on the tree type:

  • Enterprise trees have as many Organizational Unit (OU) containers as necessary to represent WAN locations.
  • eCommerce trees have only one container and a relatively shallow and flat structure.

Partition Strategies

For NDS 7 and earlier versions of NDS, Novell recommends partition boundaries to ensure optimal performance of the directory. For eDirectory 8.5, however, you are free to design partitions in whatever way makes the most sense for your company.

For enterprise trees, it makes sense to segment the directory into partitions at the geographic level and place the partitions on the appropriate local servers. In addition, follow these guidelines:

  • Partition size:
    • For trees with relationships (such as group memberships): as many as 500,000 objects
    • For trees with inter-object relationships: several million objects
  • Total number of partitions in tree: Unlimited
  • Number of child partitions per parent: 150
  • Number of replicas per partition: 50
  • Number of replicas per replica server: 250

These guidelines generally are not applicable to eCommerce trees. Because you do not know where a particular user is coming from over the Internet, eCommerce deployments of eDirectory typically store all data on a single server and, in most cases, have only one partition.

Replica Placement

To safeguard fault tolerance and accessibility, follow these replication rules:

  • For enterprise trees, replicate locally first and at each location, store at least two replicas of a local partition.
  • For eCommerce trees, store multiple instances of data for load balancing since tens of thousands of users will be accessing your tree.
  • Use cross-platform replication when access to other platforms is required.
  • Keep master replicas in central locations. If you must replicate the master replica at a remote site, use Novell's WAN Traffic Manager (WANMAN) utility to control the replication of eDirectory traffic over WAN links.

Content for this passage was drawn from "Novell eDirectory: Reviewing the Design of Your eDirectory Tree," Jeffrey F. Hughes, Novell Connection, October 2001. You can download the complete article from

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