I've used DVD-RWs in the past for making full image backups of my then 20G, later 100G C and D partitions. And, because something can go wrong with any one DVD-RW within a set during an attempted restore, I always made two sets, duplicates. There are a number of free and fee backup / restore / cloning programs that surely can also use DVD-RWs.
One warning: I used to place my listening-in-the-car mp3s onto DVD-RWs, eventually, slowly, over time, one of the DVD-RWs would begin to make an extra noise-bit now and then, a few more burps and skips, until I re-full-formatted them and started over. DVD-RWs can become problematic over time, forcing a full format and another re-load of whatever was on it to start with.
"Take care of thy backups and thy restores shall take care of thee." -- Ben Franklin revisited.
Backup, backup, backup! -- Lady Fitzgerald (w7forums)
Clone or Image often! Backup... -- RockE (WSL)
"I heard Spock finally got colander!" "I believe the word is Kolinahr." "Oh."