Storing Archive DVDs

[bk_waas]

<p>What is the best way to store archive DVDs? If I go to the expense of burning something onto an archive quality DVD, what should I use to store that DVD? Are there particular types of things to avoid? Thanks.</p>

[James Kazan]

Avoid extremes in temperature and humidity, as well as exposure to direct sunlight. Store discs upright to avoid bending, and take care in removing them from the holders to avoid scratches and fingerprints. Clean them carefully, by wiping with a clean cotton fabric in a straight line from the centrer of the disc toward the outer edge - not with a circular motion.

 

I've been using DVD Ram disks for archival purposes for some years. Now that external hard drives are so cheap I use multiple hard drives as backups. I should setup a raid and write the data across all the drives so if one crashes all the data can be restored.

[garydem]

<p>the problem is not how to store an archive dvd or which dvd to use or how to make one. the problem in ten yrs is what software will then be available to read the disc OR the image files on it? time and technology are going to pass the dvd by. the alternative is to select a image file format that has a future of at least 5 yrs. a possiblity is that is you shoot raw do not store and archive the raw, convert to dng first then store that. dng will be around for a long time. but the propietary software that was the original raw file is likely not going to be here in 10yrs.<br>

m reichman, of luminous landscape, a couple of yrs ago mentioned that he had image files that he could not read not find any software that could. and those files were less than 5 yrs old.</p>

[Ed_Ingold]

<p>Jewel cases (and similar) are probably the safest physical means of storage, because the disk is touched only at the hub. That's only half the answer, however. In order to be a functional archive, you must be able to retrieve information randomly, which means the discs must be identified and stored in a reliable and orderly fashion. Unfortunately, it is nearly impossible to keep jewel cases in any reliable order. Furthermore they are bulky and often fragile.</p>

<p>My solution is to keep the discs in archival pages which hold 8 discs (using both sides). While the optical surfaces of the discs are in contact with the material, it is soft and unlikely to scratch them. The materials are not plasticized, and don't attach the discs chemically. Most of all, the order if the discs is easy to establish and maintain, and many discs (about 400) can be stored in a single ring binder or archival box.</p>

<p>I also keep the files on external drives, using the same date ordered scheme. Hard drives are fast and convenient, and hold a lot of files. That also means you can lose a lot of files in an eyeblink. With thirty or so drives, I can count on losing one or two a year. Having backups on DVDs gives me comfort knowing they can't be accidently erased and last a long, long time if properly written, verified and stored. (Nearly all "vanishing" data can be traced to bad, poorly verified burns or physical damage in storage.)</p>

<p>Do we care what happens in 5 years, or thirty? If we want our work to be readible, have it printed (on archival media). Eyes and brains (eyes, anyway) aren't going out of style soon. Everything else is for our own convenience in our own lifetimes. CDs, DVDs and hard drives use nearly universal software, and are so widely popular, means to read them will be around for decades, any. They have already outlasted ZIP drives an mini-floppies by a factor of four. On a more pragmatic level, there was one Ansel Adams, and that slot is occupied in perpetuity.</p>

[h_s1]

<p>I thought about this a few years ago when I started amassing all my photos in digital format. I arrived at the conclusion that DVDs were not a reliable long term storage solution. Hard disks being as cheap as they are, they were the best solution. Here is what I do:<br>

1. Store all photos on a hard disk which is networked and accessible from all computers on the local network. No need to go search and insert an optical disc to look at photos.<br>

2. Do a periodic backup to a different hard disk on a different computer on the network.<br>

3. Checksums are maintained for all full resolution and raw files. Periodic checks can be run to see if there are any errors have crept in (failing hard disk, usually). No problems yet.<br>

4. The backup is done on an external hard disk. In case of emergency, it can be just plugged out and carried on person.</p>

<p>This has been the more robust, reliable and convenient method for me. I use Linux and all networking, imaging and data compression and security tools are free (helps to be familiar with them). My raw files are either in Canon's raw format or dng format. All other files are in jpegs. For all these formats, open source tools exist so there is hardy any concern for their support in future. There open source tools for conversion from one format to another. So converting my images to a different format is just a question of writing a few lines of script and running on my Linux machine. Also, since all tools that I use are open source, I have no worries about companies providing the software closing shop.</p>

<p>In contrast, when I initially used optical discs for a short duration, I had to put a lot of effort in taking care of them, choosing the right manufacturer, avoiding scratches, etc.</p>

<p>My current system is way better than my first choice of optical discs. YMMV.</p>

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[keith_b1]

<p>Store in, or as near as you can get, to total darkness: the recording is made with red light, and the only thing that can interfere with the recording is light.</p>

[Ed_Ingold]

<p>The only reliable hard drive is a RAID, which runs continuously (which allows the data to be refreshed) and maintained assiduously. That's not too expensive if you have a terabyte or less of images to maintain. However, a terabyte is not all that big if you have a lot of images. I'd need about 15 type 2 RAIDs, and time to investigate problems and replace failing drives. That would probably amount to at least ten drive units a year. A hot-swap RAID will cost 5x-10x as much as a Best Buy version.</p>

<p>Individual hard drives are anything but reliable, and "wear out" even if you leave them on the shelf. The magnetic domains weaken and interract, rendering the data on down drives unreadible in a few years.</p>

<p>Optical discs are burned using infrared lasers, not red light. Furthermore, it's heat, not the light, that burns the disc - over 600 deg F for an instant. The heat disintegrates the pigment (not dye) so that the burned area does not reflect light the same as an unburned region. The color of the pigment, indeed the pigment itself is significant only during the burning process. It is there simply to absorb light, heat and explode (locally), and otherwise remain transparent.</p>

[h_s1]

<p>Edward, you are correct in pointing out the advantages of RAID. However, note that RAID is no substitute for regular backups. And backups have the same significance even if one is not using RAID. Having even a single backup is extremely helpful. It is extremely unlikely two hard disks will fail at the same time, or with the same file!</p>

<p>Storage limit is an important factor. When I hit 1 TB limit (which will take some years yet, I am only a hobby photographer), I intend to copy the older photos to hard disks or to a tape, unless larger capacity hard disk are economically available (I think we already have 1.5 TB in the market). Storage tapes are quite a good option to save backup for the long run - much more robust than optical discs, I believe.</p>

<p> </p>

[Ed_Ingold]

<p>Storage tapes are probably the least durable of all backups. There is significant cross-printing between tracks and even layers, that progresses with time. Furthermore, formats go out of style faster than ladies' hats. Drives themselves are high-maintenance devices, with regular head cleaning and scheduled replacements. Their main virtue is that you can store a lot of data in a relatively small space on removeable media and transport it to a remote site. Tapes are used for laddered, short-term backups over a span of a year or less.</p>

<p>DVDs, probably even Blu-Ray discs, are far more reliable than tapes if you backup no more than 25 GB at a time (I switch to BDRs rather than sit and change more than 8 DVDs during a backup - not uncommon with video or even 96/24 multitrack audio sessions).</p>

<p>A RAID 1 (and higher) <strong>is </strong>a substitute for regular HD backups - data is mirrored on two or more disks in a variety of schemes, so that the loss of one drive is not fatal. Perhaps you're thinking of a RAID 0, which splits data across two or more disks for faster throughput. With a RAID 0, the loss of even one disk is fatal.</p>

<p>The key to any backup is due diligence and timeliness. Using a RAID 1 (or higher) makes that a lot easier. You can still hit the delete key (or format) at any time and trash a lot of work. You'd need a (BIG) shredder to do that with DVDs. The key to using optical media is keeping up with the task, and keeping track of where the data is located.</p>

[h_s1]

<p>Interesting points. Regarding RAID, no, RAID n is not a substitute for back, whatever n may be. As you wrote:</p>

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<p>Using a RAID 1 (or higher) makes that a lot easier. You can still hit the delete key (or format) at any time and trash a lot of work.</p>

 

</blockquote>

<p>Exactly a situation that is dealt nicely with rolling and timed backups! It is better explained on the following sites:<br>

http://www.remotedatabackups.com/why/backup-raid-drive.cfm (see Point 6)<br>

http://storagemojo.com/2007/05/30/home-raid-vs-backup/</p>

<p>I haven't tried Blue discs yet. Don't have a writer. But given their capacity, they do sound interesting.</p>

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