What is the largest file I can write to a DVD?

Question

I am creating an archive of a large file set using the 7-Zip command line tool, and I am going to write the archive to DVDs (2 sets, to be safe).

Assuming exactly one file (a part of a 7-Zip archive) per burned DVD-R, what is the largest volume size I can split my archive into?

Answer 1

First of all, make sure you burn the discs in UDF format instead of ISO-9660 format. ISO-9660 only supports files up to 2 gibibytes or 4 gibibytes depending on the implementation.

UDF format doesn't seem to have a lot of base overhead for a volume with one file in it, but let's use a figure of 10 mebibytes of overhead (10×1024² bytes or 5120 DVD-sized sectors), to allow for faults in the writing process and plenty of room for the filesystem just in case.

(Capacity values quoted from http://en.wikipedia.org/wiki/Dvd#Capacity .)

• DVD-R single layer
  2,298,496 sectors, 4,707,319,808 bytes
  subtract 10MiB overhead = 4,696,834,048 bytes

• DVD+R single layer
  2,295,104 sectors, 4,700,372,992 bytes
  subtract 10MiB overhead = 4,689,887,232 bytes

• DVD-R dual layer
  4,171,712 sectors, 8,543,666,176 bytes
  subtract 10MiB overhead = 8,533,180,416 bytes

• DVD+R dual layer
  4,173,824 sectors, 8,547,991,552 bytes
  subtract 10MiB overhead = 8,537,505,792 bytes

So, if you are using any single layer discs (or might switch between +R and -R), then the 7-Zip command line would be:

7za a -v4689887232b FOLDER.7z FOLDER