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Which type of DVD for backup?
PeterGar
Registered Users Posts: 294 Major grins
I'm finally buying a dual format DVD recorder today. Which type of recordable DVD media, DVD-R or DVD+R, is best to use for backup up data files, specifically photo files?
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When this thread gets priceless advice, then we can move it to the Hall of Wisdom!
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
- Avoid multi-writeable (CD-RW, DVD+RW, DVD-RW) media, as it typically has a MTBF that is around 1/4 that of write once media, even if you don't over write it repeatedly. (it's also a fair amount more expensive)
- get azo or phthalocyanine dye based media, they tend to be more stable than other dyes
- do not store the burnt media in clear containers where they will be subject to light. (they aren't as sensitive as raw film or something, but they can fade with time if they are exposed to bright light.)
- do not expose the media to wild ranges of heat or humidity, as these can cause issues for the glues that hold the layers of media together. (MN winters can be brutal on cheap cdrs, as I and some friends all learned.)
- minimise the amount of writing you do on the media. Ideally, no more than a sequence number. Keep any other data on paper or in a computer with a reference back to that sequence number. Always use a Sharpie (specifically one of the more recent non-toxic sharpies), and use a large "font" when you write the number. The idea is that if by some stroke of bad luck, the ink does eat through the disc, you want any possible damage to be spread out so as that the error corrective properties of the media can "deal with" this damage, much as it would a scratch. (I've always assumed that this applies to data dvds as well, and not just video, since the assertion I've always heard is that this ecc logic is in the drive, and there is no difference at that level between data, audio and video dvds.)
- Take your time burning. A disc burnt at 1x is likely to last longer than a disc burnt at 8x.
- Buy in bulk (on a spindle) not in individual jewel cases, this is less important if you buy from a reputable brand, but media in jewel cases has a higher rate of scratches before you even get it. You can buy your own (mini) jewel cases seperately, cheaper.
- record (on the paper, not the disc) when you burnt the disc, and be prepared to duplicate it while it's still working, but before it's expected to die. (if you're buying super cheap media, this might be just 5 years from now... I've personally had super cheap CDRs fade away in less than a year, though I didn't take very good care of them, 'cause they weren't anything anyone needed kept, just test install images that had a shelf life of weeks anyway.)
- Unless you are talking about really large single files, or really huge ammounts of total data, you may find that CDR is actually a better format for you to use... simply because if you loose a disc, you don't loose as much data, and the smaller amount of data means you'll fill it up faster and therefore be creating them more often, thereby in the event of a catastrophic restore, you'll be losing less data, time wise. Few of the items I've mentioned here are actually specific to dvd, they're just as applicable to cdr. This one is a trade off of course, shoot enough and you'll quickly find yourself spending as much time making backup cds as you do in other post processing.
A couple more items to think about if you're backing up large quantities of data, or data that is very very important.- Do not allow one single media failure to take away every copy of any piece of data. This could be as "simple" as making two copies of every disc (ideally a year or so apart, or on different brand and type of media) or it could be more complex, such as using a complex raid 5 type of algorythm to distribute data across multiple discs (I know of one comercial backup solution that does this with tape, but it is insanely expensive, I've always wanted to implement it across cds, but to really do it "well" on the read back part you would need 5 cdrom drives attached to your system.)
- Be prepared to periodically validate each disc is still good, one of my favorite ways to do this is to take a cryptographic signature of the content of every file on the disc, then take the signature of the resulting list and store that somewhere you can look it up based on the discs id number, or even print it out and store it in with the disc for later comparison. (this is far easier than it sounds, honest.)
Oi, I've rambled... and a bit off the topic of what you actually asked, so I'll shut up now... right after I point to this article, which is a really good read on the topic, and possibly this FAQ entry might also be interesting.http://wall-art.smugmug.com/
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
Excellent information!
On my home computer i've installed a little program that reads blank DVDs and extracts manufacturer information. This information can be fed into a web-site and this web-site then provides info/reviews on the manufacturer and this particular set/brand of DVDs they make.
When i get home and get a chance to fire up this little program, i'll provide some more info on it (program name and web-site name).
When I hear the earth will melt into the sun,
in two billion years,
all I can think is:
"Will that be on a Monday?"
==========================
http://www.streetsofboston.com
http://blog.antonspaans.com
Cabbey, this is top-notch advice. Fantastic contribution. Many things I never knew. Thanks!
"You miss 100% of the shots you don't take" - Wayne Gretzky
For a wealth of information about reliability of DVD and CD media, you can do the following:
- Download DVDInfoPro here: http://www.dvdinfopro.com/
- Install and use this tool to obtain your blank DVD's "Media Code".
- Then go here http://www.videohelp.com/dvdmedia and use this "Media Code" to see the review/reliability/etc of your DVD disks.
Also, browse http://www.videohelp.com to see which manufacturers make reliable CD/DVD media.
When I hear the earth will melt into the sun,
in two billion years,
all I can think is:
"Will that be on a Monday?"
==========================
http://www.streetsofboston.com
http://blog.antonspaans.com
ooh, they have one right there on the page, sweet.
http://wall-art.smugmug.com/
As stated above burn as slow as possible as this is much better, I did a burn of a DVD at 8X and could not hardly see the burn marks.....burned again at 2X and the burn marks were very clear...that was as slow as my burning software allowed so now I look for slow burn numbers on my media.
I would not use dual layer for anything way too much info to get lost.