Image files, which are small files that contain information about the backup set, are distributed to the central administration server from every managed media server. History files, which contain detailed information about the backup set, remain on the managed media server.
When the catalog is distributed, the view of the restore selections on the central administration server displays only the backup set at the volume level. Backup set details are not displayed if the managed media server that created this backup set is not available, but the whole volume can be restored from the central administration server.
A distributed catalog provides increased performance, default centralized restore capability, and decreased network traffic. If a managed media server does not have a persistent connection to the central administration server, then whenever the managed media server does connect, the image files in the catalog are automatically distributed to the central administration server. The temporary increase in network traffic caused by the catalog distribution is not significant.