Backup > Max File Size

Max File Size applies to Volume backups only.  When a Volume backup runs, image files of the volume get created.  These file size specified in this option is the maximum size of each image file.  For example, a volume containing 10 GB of data has been set to run.  The image that gets created for a full backup may be 5 GB.  If the max file size is set to 600 MB, the system will create 9 files, 8 that are 600 MB and 1 file with the balance of the data.

If you are going to write the image files to a CD or DVD, select the file size that is appropriate for the media.