The popular DVD burning software for Windows like Nero and Easy Media Creator are not safe to burn the Unix file system directly on CD or DVD. If you burned a disc in this way, try to md5 files on disc and the original files. You may realize that some of the MD5 hashes are not identical!
The older version of mkisofs could not create the image file larger than 2GB. However, the current version fix this problem by using a new -UDF option. Following is the syntax to create a data DVD ISO image file for the entire dirname folder:
mkisofs -o file.iso -UDF -f -a -J -r -v -V "Volume ID" dirname
It's safe to burn the image file with mkisofs because all files on disc will be identical to the original files.
For more detailed options, please look at its man page or run "mkisofs -help".