[ILUG] Alternative filesystems on a DVD
malcoh0l at yahoo.ie
Thu Aug 10 16:43:42 IST 2006
Thanks for the various replies so far:
I'll reiterate my worry:
* CDs/DVDs are likely to fail in a different way to hard disks.
* It's possible that iso9660 is designed to reduce the risk of curruption due
to the kind of failures that CDs/DVDs are vulnerable to.
* It's possible that ext3 is designed to reduce the risk of curruption due
to the kind of failures that hard disks are vulnerable to.
If this is true, then shouldn't I be a little worried about trusting my back-ups
Glenn Strong wrote:
> No real problems (modulo the usual questions as to whether DVD/CDR
> media count as long term)
Good point. I wouldn't trust a DVD back-up for too many years, anyway.
Colm MacCarthaigh wrote:
> I certainly wouldn't want to bet on it being easy in 10 years time to read a
> current ext3 filesystem.
Also a good point. But that's longer term than necessary.
> Or do you want something you can more easily restore individual files from?
That's definitely a feature for me.
Daniel Shaw wrote:
> Create a loopback filesystem within a 4 gig blank file...
Yep. Here's what I did to create the ext3 DVD:
dd if=/dev/zero of=imagefile bs=2048 count=2200000
/sbin/mkfs.ext3 -b 2048 imagefile
mount imagefile /mnt/mountpoint -t ext3 -o loop
...copy files into /mnt/mountpoint...
growisofs -Z /dev/dvdrw=imagefile
I guessed the size of the file (2,200,000 * 2,048 = 4,505,600,000) because
I couldn't remember exactly how much a DVD can hold. The answer is
4,700,000,000 bytes apparantly.
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