When crosschecking on multiple nodes (and when operating RMAN in general), configure the cluster so that all backups can be accessed by every node, regardless of which node created the backup. When the cluster is configured this way, you can allocate channels to any node in the cluster during restore or crosscheck operations.
If you cannot configure the cluster so that each node can access all backups, then during restore and crosscheck operations, you must allocate channels on multiple nodes by providing the CONNECT option to the CONFIGURE CHANNEL command, so that every backup can be accessed by at least one node. If some backups are not accessible during crosscheck because no channel was configured on the node that can access those backups, then those backups are marked EXPIRED in the RMAN repository after the crosscheck.
For example, you can use CONFIGURE CHANNEL ... CONNECT in an Oracle RAC configuration in which tape backups are created on various nodes in the cluster and each backup is only accessible on the node on which it is created. This is described in more detail in "Configuring Channels to Use a Specific Node".
See Also:
Oracle Database Backup and Recovery User's Guide for more information about crosschecking