Volume SnapMirror replication backs up an entire SnapVault for NetBackup volume to another storage system as a read-only volume. You can access this backed-up read-only volume using NetBackup. This capability is useful if you want to restore backups from the read-only volume to a different NetBackup master and media server combination or if you want to transfer the restored backups to NetBackup managed tape media as a long-term archive.