The Backup Exec servers can share media within the shared storage devices, but not simultaneously. For example, media server A can write a backup to a media, and when that job is finished, media server B can append another backup to the same media. Or, if overwrite protection is not enabled, media server B may overwrite that media.
Media sets are not server-centric. In the shared storage environment, all users have a view of all media and media sets. Each media set can contain media in the shared devices and media in any local devices attached to servers.
Media stored in locally-attached secondary storage devices are not accessible by other media servers.