6.5 Administering Replicas

Before you add or delete a replica, or change replica type, carefully plan target replica locations. See Section 2.4, Guidelines for Replicating Your Tree.

6.5.1 Adding a Replica

Add a replica to a server to provide your directory with

  • Fault tolerance

  • Faster access to data

  • Faster access across a WAN link

  • Access to objects in a set context (using bindery services)

To add a replica:

  1. In NetIQ iManager, click the Roles and Tasks button Roles and Tasks button.

  2. Click Partition and Replica Management > Replica View.

  3. Specify the name and context of the partition or server you want to replicate, then click OK.

  4. Click Add Replica.

  5. Specify the partition or server name and context.

  6. Choose one of the following replica types:

    Replica Type

    Description

    Read-Write

    Users will be able to both read and modify the contents of the new replica. Select this option if there are no modifiable replicas close enough to the users who manage the eDirectory objects in this partition.

    Read-Only

    Users will be able to read but not modify the contents of the new replica. Select this option if there are no replicas close enough to the users who read but don’t modify the eDirectory objects in this partition.

    Filtered Read-Write

    Users will be able to both read and modify the contents of the new replica, and the contents will be limited to the types of eDirectory objects and properties specified in a filter.

    Filtered Read-Only

    Users will be able to read but not modify the contents of the new replica, and the contents will be limited to the types of eDirectory objects and properties specified in a filter.

  7. Click OK.

For more information, see Replica Types.

6.5.2 Deleting a Replica

Deleting a replica removes the replica of the partition from a server.

If you want to remove a server from the directory tree, you can delete replicas from the server before removing the server. Deleting the replicas reduces the chance of having problems when removing the server.

You can also reduce synchronization traffic on the network by removing replicas. Keep in mind that you probably don’t want more than six replicas of any partition.

You cannot delete a master replica or a subordinate reference.

If the replica you want to delete is a master, you have two options:

  • Go to a server with another replica of the partition and make it the new master replica

    This automatically changes the original master replica to a read/write replica, which you can then delete.

  • Merge the partition with its parent partition

    This merges the replicas of the partition with those of its parent and removes them from the servers they reside on. Merging removes partition boundaries, but not the objects. The objects continue to exist on each server which held a replica of the “joined” partition.

When you delete replicas, keep the following guidelines in mind:

  • For fault tolerance, you should maintain at least three replicas of each partition on different servers.

  • Deleting a replica deletes a copy of part of the directory database on the targeted server.

    The database can still be accessed on other servers in the network, and the server that the replica was on still functions in eDirectory.

    You cannot delete or manage subordinate reference replicas. They are created automatically on a server by eDirectory when the server contains a replica of a partition but not of that partition’s child.

To delete a replica:

  1. In NetIQ iManager, click the Roles and Tasks button Roles and Tasks button.

  2. Click Partition and Replica Management > Replica View.

  3. Specify the name and context of the partition or server that holds the replica you want to delete, then click OK.

  4. Click Delete Replica icon to the left of the replica you want to delete.

  5. Click OK.

6.5.3 Changing a Replica Type

Change a replica type to control access to the replica information. For example, you might want to change an existing read/write replica to a read-only replica to prevent users from writing to the replica and modifying directory data.

You can change the type of a read/write or a read-only replica. You cannot change the type of a master replica, but a read/write or read-only can be changed to a master, which automatically changes the original master to a read/write replica.

Most replicas should be read/write. Read/write replicas can be written to by client operations. They send out information for synchronization when a change is made. Read-only replicas cannot be written to by client operations. However, they are updated when the replicas synchronize.

You cannot change the replica type of a subordinate reference. To place a replica of a partition on a server which currently has a subordinate reference requires an Add replica operation. A subordinate reference replica is not a complete copy of a partition. The placement and management of subordinate reference replicas is handled by eDirectory. They are created automatically on a server by eDirectory when the server contains a replica of a partition but not of that partition’s child.

To change a replica type:

  1. In NetIQ iManager, click the Roles and Tasks button Roles and Tasks button.

  2. Click Partition and Replica Management > Replica View.

  3. Specify the name and context of the partition or server that holds the replica you want to change, then click OK.

  4. Click the replica type (in the Type column) of the replica you want to change.

  5. Select a new replica type, then click OK.

    Replica Type

    Description

    Master

    Users can both read and modify the contents of this replica, and the replica is the starting point for any future partitioning activity that affects this partition, such as creating or merging a subpartition. Only one master replica is allowed per partition.

    Read-Write

    Users can both read and modify the contents of the new replica. Select this option if there are no modifiable replicas close enough to the users who manage the eDirectory objects in this partition.

    Read-Only

    Users can read but not modify the contents of the new replica. Select this option if there are no replicas close enough to the users who read but don’t modify the eDirectory objects in this partition.

    Filtered Read-Write

    Users can both read and modify the contents of the new replica, and the contents are limited to the types of eDirectory objects and properties specified in a filter.

    Filtered Read-Only

    Users can read but not modify the contents of the new replica, and the contents are limited to the types of eDirectory objects and properties specified in a filter.

  6. Click OK.

For more information, see Replica Types.