Does this DVD backup software exist?

September 30, 2005 4:45 PM

Backing up data to unreliable media (DVD)

An earlier question has me wondering. Is there any DVD backup software that allows an arbitrary (but pre-determined) number of discs to fail, without data loss?

e.g. a backup set of N discs, with sufficient redundancy to allow M discs to fail without issue, with M being configurable.

posted by I Love Tacos to Computers & Internet (7 answers total)

Best answer: Hmm. Perhaps you could use Parchive. I've only used them with Usenet, but I don't see why it wouldn't work.
posted by atom128 at 5:23 PM on September 30, 2005

Best answer: I also create parity files (PAR2) when I backup my scientific data to disc. Usually 15%, on separate discs and in duplicate.
posted by PurplePorpoise at 5:55 PM on September 30, 2005

Response by poster: Thanks, that's perfect!
posted by I Love Tacos at 5:58 PM on September 30, 2005

I'd use Winrar to make an archive in DVD-sized pieces (4.3GB) and then Quickpar to generate extra recovery records which would be burned as additional discs.
posted by Rhomboid at 6:09 PM on September 30, 2005

purpleporpoise... what happens if you have one large file, like a video file? my understanding is that par2 only works over a collection of files, because the recovery unit is a file, not sectors of a file.
posted by joeblough at 9:10 AM on October 1, 2005

joeblough - I took my cues from usenet and winrar into smallish chunks. Winrar can sometimes fix itself so I have a bit of redundancy. Sure, it makes getting/previewing the data more of a pain but...
posted by PurplePorpoise at 11:42 AM on October 1, 2005

As far as I know, par2 doesn't distinguish between one file and many files. That is, it just splits the whole thing up into blocks. So for example if only 2 out of all the blocks in a 700mb file are corrupted, it can just rebuild those without having to rebuild the whole file.
posted by Rhomboid at 6:38 PM on October 1, 2005