How much space will be temporarily used in mirror (image) drive while you are burning an image to writer?
In data archive process, the image drive is playing the role of keeping all archive images for on-line data query purpose. It is several times faster than searching and reading directly from CD or DVD-ROM drive. In addition to keeping all archive images, the image drive will also temporarily keep the split images before they are successfully burned to the CD/DVD writer. So, you have to be sure that there must be enough free space left in the image drive; otherwise, the split images will failed to be burned to CD/DVD writer.