How To Choose Archival CD/DVD Media

An anonymous reader tips us to an article by Patrick McFarland, the well-known Free Software Magazine author, going into great detail on CD/DVD media. McFarland covers the history of these media from CDs through recordable DVDs, explaining the various formats and their strengths and drawbacks. The heart of the article is an essay on the DVD-R vs. DVD+R recording standards, leading to McFarland's recommendation for which media he buys for archival storage. Spoiler: it's Taiyo Yuden DVD+R all the way. From the article: "Unlike pressed CDs/DVDs, 'burnt' CDs/DVDs can eventually 'fade,' due to five things that affect the quality of CD media: sealing method, reflective layer, organic dye makeup, where it was manufactured, and your storage practices (please keep all media out of direct sunlight, in a nice cool dry dark place, in acid-free plastic containers; this will triple the lifetime of any media)."

Moo

"Unlike pressed CDs/DVDs, 'burnt' CDs/DVDs can eventually 'fade,' due to five things that affect the quality of CD media: sealing method, reflective layer, organic dye makeup, where it was manufactured, and your storage practices (please keep all media out of direct sunlight, in a nice cool dry dark place, in acid-free plastic containers; this will triple the lifetime of any media)."

How apropos.

'slashdotters' can eventually fade due to five things that affect the quality of slashdot comments:

• sealing method - The Sealing, in reality is the ceiling, and refers to the need to ceil() slashdot user's age to hit the double digits.
  
• reflective layer - The Reflective layer is the use of low UIDs to represent importance of comments, rather than something actually informative.
  
• organic dye makeup - Most comment's make up are so bad, they're DOA, and one can hear the organ playing.
  
• where it was manufactured - There are no new comments on slashdot, everything is either culled from its dupe, or copied from the Microsoft Hater's handbook.
  
• and your storage practices - Some comments are posted before they are fini
  

I'm Surprised

I'm surprised to hear that consumer media can last so long. I was under the impression that consumer media would only last at most 20 years. Good to know it is longer.

Re:I'm Surprised

I'm surprised to hear that consumer media can last so long. I was under the impression that consumer media would only last at most 20 years. Good to know it is longer.

All current forms of optical storage share the same problem that will limit their reliable life span. This problem will effect different media design types over different periods of time, but 20 years is a good average before you will start to see bit rot. How ever ALL optical media, regardless of being commercialy pressed or being consumer grade CD/DVD-R, will eventualy suffer bit rot for the exact same reasons. The problem is that the rate of expansion and contraction of the metal substrates that make up the innner layers and the plastics that make up the outter layers are very different. All optical media will suffer bit rot over time because of this, as what eventualy happens is the metal substrate inside the plastic protective layers gets warped and ripples start to form in the surface. This of course starts to alter the smooth/pit reflection encoding of data on the disc and ruins the data.

Again, different types of optical media design will last longer than others. Yes, commercialy pressed CD/DVDs will last longer than consumer grade CD/DVD-R media on average. How ever none of these formats have the reliability and shelf life of magnetic backup tapes! Espeically newer formats like AIT, SAIT, and LTO (and VXA isn't too bad either, awesome pricing on smaller VXA auto loaders). So if you are looking for reliable long term archiving CD and DVD are NOT what you want to use! You want to use tapes. How ever, you can use CD or DVD if you keep in mind that this format has a shorter shelf life and you plan a migration of that data to a new removable media format say 10 years out from now. You have to do the same thing with tapes too, as eventualy formats become old enough that it gets hard to find tape drives that will read your backups. And yes there is still a limit to the shelf life of backup tapes, as over time the magnetic signals encoded in the tape start to transfer between layers due to the tape layers being tightly wound around each other on the take up spool. How ever, even with that in mind, tapes provide a much longer useful life span for archiving data. And beyond having a longer shelf life tapes have several other advantages. They have much larger capacities than CD/DVD media, so you don't have to sit there rotating tons of discs to restore a large archive. And in many cases newer tape formats have much faster transfer rates than CD/DVD (granted they cannot do random I/O, but burning CD/DVD isn't a random I/O process either). Any one who has serious data to protect shouldn't be using CD/DVD for backup. This is more of a cheap low end consumer approach for those who cannot dish out $1000+ for a good tape drive.

Those who still have the wool pulled over theirs eyes and still think CD/DVDs are a long term storage platform need only look to those of us who have very old CDs and laser discs for proof to the contrary. I know plenty of people who bought some of the first pressings of CD albums back in the early 80s, and many of their earlier CDs are now suffering bit rot. This is even more prevelant on laser disc, probably because of the much larger surface area being affected. Many laser disc owners are fully aware of the problem of optical media bit rot. In many cases the bit rot gets bad enough that you can visualy see the distortions on the reflective surface.

Bottom line, if you value your data then use backup tapes! That's what that technology was invented for! CD/DVD-R is more of a short term backup option, best for cheap short term archiving or transporting of data. I use CD/DVD-R for regular backups of the documents on some of my workstations. But when it comes to our servers and our customer's servers it's AIT or LTO tape drives all the way!! Use the right tool for the job!!

He forgot the most important one...

"(please keep all media out of direct sunlight, in a nice cool dry dark place, in acid-free plastic containers; this will triple the lifetime of any media)." And NEVER ever feed them after midnight. On a more serious note, I used to worry about eventual degradation but it's coming up on 10 years that I've owned a CD-R drive and I have yet to run across a burned CD I cannot read due to this sort of degradation. Maybe at the decade mark, some of my discs will fail me and I'll change my mind but right now I'm not too concerned.

Re:He forgot the most important one...

Used to run an archiving business of sorts (trade stuff in exchange for space) on many towers of CDs. I burned in the mid to late 90s many CDs and have them all archived still. Went back and uploaded them to a terabyte raid I built and without one failure of the CDRs that I archived, not one degraded to not mount and copy. I had a few that had scratches, but that is a different story and not related. Bottomline, buy what works, cheap and don't move them once archived, keep in cool dark place, and you are good to go. Oxidation is a CD-ophile's issue, not much in the reality zone. Heat is an issue, and if you store them on your dashboard, you deserve what results.

Re:

"(please keep all media out of direct sunlight, in a nice cool dry dark place, in acid-free plastic containers; this will triple the lifetime of any media)." And NEVER ever feed them after midnight.

Do not taunt Happy Fun CD.

Bummer

I always thought Matsui "Gold" and "Silver" were the top-rated media. At least for CD-Rs (though I thought they were held in high regard for DVD blank media, too). I used to mail-order un-branded blanks them by the spool.

Re:Bummer

Mitsui's gold media has generally been considered the best available for CD-R work, particularly from an archival perspective. The company has reorganized and now goes by the name MAM. If you look through the comments after the article, the author suggests that the currently available MAM media isn't as high of a quality as the older Mitsui discs. I would like to see some citation for that fact, as I wasn't aware the formulation was changed at all from that reorg, but I haven't researched this subject recently enough to be able to dismiss his suggestion outright.

Safety in Numbers

Cheap but adequate DVD-R media costs $200 for 1000 discs, about 4TB capacity. And a cheap DVD-R changer jukebox costs under $500, about 800GB per load.

Why not just burn a few copies of the archive to a bunch of DVD sets? The DVDs will get defects, but shuffling the chunks across the discs just a little will probably ensure that the random distribution of specific defects will not hit every copy of a given bit, against the odds a low defect rate will produce.

How about a pair of those archivers, which fire up every few years just to transfer the aging DVDs to fresh new ones? For another $1000, that's another 5 cycles of DVDs, 800GB per cycle. Another $1000 gets a pair of backup jukeboxes.

For higher capacities than 800GB, there are pricier pro jukeboxes, but with dual drives for the retranscription cycle (and faster restores). But the architecture is the same. Why try to make the media more reliable, when there's cheaper/easier solutions that just accept unreliable media, and move on?

Re:Safety in Numbers

Why not just get a NAS that has RAID? That would make more sense. When a disc dies, you can replace it, rebuild your array, and everything is fine. PLUS, you could expand your archive over time.

I think it's absolutely stupid to use a DVD jukebox. Really. Look into a NAS box with RAID.

Re:Safety in Numbers

With the single DVD jukebox, the first 800GB is online at one time, for $450. A 750GB HD costs $350. But the next 800GB in DVD costs only $40 - each 4TB costs $200. And there's no limit to how many $50 TBs you can archive, with a sizeable enough closet. The downside is un/loading the jukebox, 200 at a time. But that's archive, "nearline" storage.

Plus, you get a DVD reader and writer. For dealing with the DVDs (and CDs) that still distribute lots of content as a transfer medium. And for those without distributed endpoints to where they can archive data, or insufficient network bandwidth to archive all their data across the WAN frequently enough, DVDs are good and cheap offsite archive repositories. Plus you can burn DVDs that will play in every consumer player, which can connect your data to lots of people without data processing HW. HDs are a cul de sac for data, trapped within the infosystem.

DVD archiving isn't really competition to online HD storage. It's complementary, in different use cases, different user environments. There's considerable overlap in their related extremes, but there's a lot of difference that makes leaves the DVD solution worthwhile for many scenarios.

BTW, while I'm offering detailed factual analysis of HD vs DVD mass storage, don't throw in your "opinion" that "it's absolutely stupid...". Especially if you're going to offer a disagreement worth considering. Do you want to work together to figure out the real merits in a debate, or do you want to get into an obnoxious pissing contest that few other people will want to wade through? Few people worth teaching will learn anything from such unnecessary conflict. Including ourselves.

I agree... But where can I find some?

Taiyo Yuden All the way. They are great for copying PSX/PS2 games (seriously) where media quality makes a difference between burning out a laser or playing your back-up game, as well as DVD Movies.

The only drawback is that you can only order them from the Internet. I do not know of any retail store who actually sells the brand outright nor do I know of any brand (like Sony, Memorex, Fujifilm) who sells rebranded Taiyo Yuden discs.

Also, the Taiyo brand is more expensive than any other brand.

Re:I agree... But where can I find some?

Some Verbatim DVD+Rs are manufactured by Taiyo Yuden. Strangely, the ones I used were the cheap-looking colored ones, but I've used several batches of those with excellent results. Speaking of Verbatim, some of their other discs are made by Mitsubishi, and those also very good, although I'm not sure how they'd work for PS2 piracy ;)

The secret to spotting Taiyo Yudens

I've seen Taiyo Yuden CD-Rs and DVD+/-Rs in a number of retail stores under various brand names. I'm hesitant to publicize my trick, but I suppose the Slashdot community should know. Here's how to spot Taiyo Yudens quickly in the store, without checking each label for "Made in Japan":

The spindles all have a unique bottom lip. Whereas most plastic spindle coverings are the same diameter from the top of the spindle to the bottom, Taiyo Yuden cases have a "lip" on the bottom of the plastic covering that starts about an inch from the bottom. The bottom of the clear plastic covering sticks out just a bit and then recesses to the diameter of the rest of the spindle. Taiyo Yudens comes in these cases no matter how they are branded, and I have never seen a spindle of discs with this bottom lip that are not Taiyo Yuden. I guess Taiyo Yuden supplies the plastic spindles as well as the branding on top of the disc.

In any case, I have had better luck with the consistency of Taiyo Yudens than any other brand of DVD+R. I'm not sure what the case is now, since I've only been using Taiyo Yudens for the past few years, but when DVD recording was first becoming affordable, the compatibility of much DVD media with various recorders was so terrible as to be useless (and endlessly frustrating). Taiyo Yuden makes quality discs, and it's always nice to spot them in the store when there's a deal going on.

MediaSupply.com

I order Taiyo Yuden DVD+Rs from MediaSupply.com. $25 for a spindle of 50.

Not a concern with MY optical media

I have some movies on laserdisc that're pushing 20 years, and I haven't had a problem with them yet!

You don't get

direct sunlight in your parents basement. ;)

This bears repeating

Repeating again and again and again:

For backups and archival you need tape backups, stored offsite. If you want something with more capacity and faster recovery, a backup server with rsync and beefy hard drives. Nothing else will do. With the time and effort you'll spend searching and writing DVD media you could have already bought and set up a file server or bought that tape drive.

Unless you're going to be taking those backups with you and using them in high volume, backing up to DVDs is simply a waste of time and space, and when you get some dreaded CRC errors you'll be crying for not having done otherwise.

sig: Cosas varias de un sysadmin argentino: http://aosinski.phpnet.us/ [phpnet.us]

I have CDs good since 1998

I now have some no-name-brand CDs burned in 1998 that are still good. I have never had a good, name-brand CD fail for any reason. The only failure I have ever had was the top layer peeling off some el-cheapo CDs which were stored in plastic sleeves, not jewel cases. One BIG key the article does not mention is to store the disc where the burned surface is not touching anything, such as in a jewel case -- the article should have mentioned that. Do not put in plastic sleeves or cases with slide-in sleeves. Odd that the article is a sales pitch for that T-Y brand -- what about RiData? That's what I use for DVD archival storage. I haven't been using DVD-R long enough to comment on how long they'll last. I have always found the alarmist idea that CDs will spontaneously self-destruct to be sort of over-the-top. CDs seem much more reliable for archiving than any other medium like diskette, hard disk, USB flash, or tape. Flash is more reliable, but has to be refreshed or it will disappear.

Re:I have CDs good since 1998

I now have some no-name-brand CDs burned in 1998 that are still good.

Probably using the original dyes, then? According to the article, they are most likely to fail in 2008:

The first organic dyes, designed by Taiyo Yuden, were Cyanine-based and, under normal conditions, had a shelf life of around ten years; simply, that was simply unacceptable for archive discs.

These people are talking about serious long-term archiving, not "it worked for this one guy for eight years".

I haven't been using DVD-R long enough to comment on how long they'll last.

No one has successfully used them as long as these people are talking about; they haven't existed that long. The lifespan claims are made from an understanding of chemistry (theory) and accelerated aging techniques (experiment).

my experience: some DVD media dies with no reason

One Maxell DVD-R I burned in Sept. 2003 went bad within 3 years, despite every detail of the burning, readback, handling, and storage being in accord with the advice I've seen posted. An email to Maxell support on this issue had the reply: "The media if stored properly will have a life of at least 50 years."

Possibly relevant, I noticed an internal pattern of small spots visible with a loupe or macro lens (on order of 10 microns in size; much larger than the data pits). You can read more about it here: http://www.bealecorner.com/trv900/DVD/Maxell-DVDR- spots.html [bealecorner.com]

Maxell America agreed to take back this DVD for analysis. As instructed I sent it to their Fair Lawn, NJ site. It was received Oct. 5 2006 and Maxell acknowledged receipt. They have apparently done nothing with it since, despite several emails to them in the ensuing two months.

I use DVD+/-R over CD-R for archiving.

The reason being that DVD+/-R has the recording surface sandwiched between the two layers of plastic. CD-Rs have the recording surface on top, which can flake off unless you handle it very carefully.

Sure, you can handle the CD-Rs carefully and avoid this problem. But wouldn't you rather use a more reliable medium in the first place?

The usual vague personal testimony...

Oh, I'm so tired of these articles. Everyone concentrates on dye fading, because I guess it's easy to measure and quantify. If dye fading were the failure mechanism for these disks, they'd last twenty to two hundred years... according to vendors and researchers.

Everyone says "I've never had any trouble with brand ABC," but the thing is, ABC varies depending on what you read or who you talk to. Some people insist they've never had any trouble with the cheapest generic products they buy at Staples. Some say any name brand is OK. Some say Verbatim is good. Some say to stay away from Verbatim. The more sophisticated will tell you not to use anything but phtalocy- pthalocy- pffthal- the Mitsui stuff. Others (like this guy) are partial to other dyes. Some say you're a fool to use anything but Mitsui Gold... some say they're an overpriced waste of money.

It's all authoritative sounding talk, talk, talk and no two experts say the same thing.

In reality, I don't think anyone understands very well what actually causes these disks to fail in the real world. I've had disks fail in less than two years--maybe only a couple-three in many hundreds, but certainly not zero--and I've never seen any obvious pattern as to which of them fail.

The thing that really bothers me is that drives and/or their accompanying software drivers never give you any indication of what the signal quality of a particular disk is. If they did, you could detect that a disk was deteriorating before it failed, and make a copy. As it is, they just keep silently keep correcting errors behind your back and you have no warning until there is utter, catastrophic failure.

Re:

Brilliant. Now try reading them on another drive. See ya! /idiot

Re:

Yeah, I get non-error-producing (in the burning process, I mean) misburns often enough that I ALWAYS keep the "verify burned data" option checked.

Takes way, way longer to burn a DVD that way, but it's worth it.