Policy management for node replication

The management class and storage hierarchy that are used by a client node on a target replication server depend on whether the domain for the node exists on the target replication server.

When a client node is registered during replication processing, the domain for the node is sent to the target replication server. If the domain name is not the same on both the source and target replication servers, the node on the target replication server is placed in the standard domain on the target replication server and bound to the default management class.

To maintain the same number of file versions on the source and the target replication servers, the source replication server manages file expiration and deletion. If a file on the source replication server is marked for deletion, but not yet deleted by the expiration processing, the target replication server deletes the file during the next replication process. Expiration processing on the target replication server is disabled for replicated data. The file on the target replication server is deleted by the source replication server after the file is expired and deleted on the source.

If a client node is removed from replication on the target replication server, the policies on the target replication server are enabled. Data on the target replication server is then managed by the policies that are on the target replication server, and expiration processing can delete expired files.

Important: Policies that are defined on replication servers and that are dissimilar can cause undesirable side-effects. As newer versions of backup files are replicated, versions that exceed the value of the VEREXISTS parameter for the copy group are marked for immediate deletion. If the node that owns the files is configured for replication, expiration does not delete the files. However, because these files are marked for immediate deletion, they are not available for the client to restore. The files remain in the storage pool until replication deletes them based on the policy on the source replication server.

With Tivoli® Storage Manager Version 7.1.1, you can configure the source and target replication servers to allow the target replication server to manage replicated data by using the target server policies. Run expiration processing on the target replication server to delete the expired files appropriately.

Tips:

Policies and storage pool hierarchies on the source and target replication servers can be different. You can use deduplicated storage pools on the source replication server, on the target replication server, or both. However, to maintain synchronization of the data on source and target replication servers, configure the management classes on the source and target replication servers to manage data similarly. To coordinate policies, consider using Tivoli Storage Manager enterprise configuration.
Ensure that sufficient space is available in the storage pool on the target replication server.
If a replicated file on the target replication server is deleted, it is eligible for replication the next time replication runs for the client node that owns the file.