What format on BD-R data backups?

WebHead

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I've decided to back up my most important data to BD-R as I don't trust HDs not to fail.

For longevity, should I use a generic file format like UDF? Or should it be safe to use APFS or HFS? I'm hoping to get a few decades out of them.
 

Fishrrman

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Feb 20, 2009
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If you're always going to use a Mac, I would suggest HFS+.

If you want the disc to be readable on PCs as well, perhaps make it exFat? (I'll admit I know little about PC formats, never touch 'em).

If you're going to use something like Toast, make the disk a "hybrid" format that will be readable on both Macs and PC's.
 
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WebHead

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Thanks, yes, I was leaning towards one of the Apple file formats.
 

HDFan

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I've decided to back up my most important data to BD-R as I don't trust HDs not to fail.
One backup is not sufficient. There are various backup guidance rules. The one I like is 3 backups in 3 different media types in 3 different locations. At least one should be off-site, in something like a fireproof bank vault.
 

mpainesyd

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For what it is worth, I just checked a 25GB BD-R disk that I created for email backup in 2015. Disk Utility lists it as Universal Disk Format (UDF). I don't think it gave me any option to change this when I created the disk - I simply used the burn disk function of Finder during the process.

Not surprisingly, the files on that disk can be read with Mojave. In any case I expect that UDF will be supported (very) long-term.
 

WebHead

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One backup is not sufficient. There are various backup guidance rules. The one I like is 3 backups in 3 different media types in 3 different locations. At least one should be off-site, in something like a fireproof bank vault.
Part of the reason I settled on optic disc was to remove the need for multiple backups. Sure, there are still risks, but much less than with magnetic media. And I intend using an on-site, non-removable, fireproof safe.


For what it is worth, I just checked a 25GB BD-R disk that I created for email backup in 2015. Disk Utility lists it as Universal Disk Format (UDF). I don't think it gave me any option to change this when I created the disk - I simply used the burn disk function of Finder during the process.

Not surprisingly, the files on that disk can be read with Mojave. In any case I expect that UDF will be supported (very) long-term.
Yes, the Finder probably gives you no choice but commercial solutions like Toast do. Still, UDF may be the most long-term option.

Thanks all for your input!
 

Fishrrman

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Feb 20, 2009
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I believe the physical construction of a BD disc is somewhat different than that of a CD/DVD blank disc.

That is to say, that the CD/DVD discs use dyes for their "burnable media", whereas a BD disc uses inorganic material -- yielding a considerably longer life (since there are no dyes that can "fade" over time and lose data).

In that way, a BD disc more resembles an "M-DISC" -- pretty much the same type of media construction.
This would give a data BD disc longer life than most other media.

(I welcome corrections)
 

WebHead

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BDs use both organic and inorganic dyes, the inorganic as you say lasts considerably longer. I’ve opted for Panasonic as they’re inorganic and considered the top brand. Have also chosen 50GB discs as the best balance of capacity and cost.

I believe the M-disc actually uses a stone layer and lasts for millennia. We’ve gone full circle back to writing on stone! But that’s a little excessive (and expensive) for my needs.
 
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mpainesyd

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Nov 29, 2008
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I believe the physical construction of a BD disc is somewhat different than that of a CD/DVD blank disc.

That is to say, that the CD/DVD discs use dyes for their "burnable media", whereas a BD disc uses inorganic material -- yielding a considerably longer life (since there are no dyes that can "fade" over time and lose data).

In that way, a BD disc more resembles an "M-DISC" -- pretty much the same type of media construction.
This would give a data BD disc longer life than most other media.

(I welcome corrections)
Last time I looked at it BD should last more than 20 years ( meaning devices to read them will likely be an issue) whereas CDs and DVDs are more like 5 years. Sure I have DVD movies that are well over 5 years old and still seem to play OK but they are not a good strategy for data backup.
 

HDFan

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Jun 30, 2007
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Part of the reason I settled on optic disc was to remove the need for multiple backups.
Yes, understand. There are additional risks writing to an optical disk. For example, what if the drive for some reason was out of alignment or marginal in some way? I have had disks which I have written (just DVD, not BD) which when I tried to read a decade later were not readable. I had to toss them. Since you are knowledgeable it might not have been an alignment issue, but you get the idea.

When you need to restore from backup in X number of years is there even going to be a BD drive available to read them? I have read numerous articles about attempts to recover contents from old computer tapes. In most cases they had to scrounge around museums to find equipment that could read them. I don't see many VHS tape recorders available for purchase right now. BD players are being discontinued, e.g. Oppo, Samsung. Although not the same thing, that means that whole market is shrinking.

Let's say that you still have your BD drive around and it still works when you need to do a restore. Will the equipment that you want to use to read the drive even be able to see it? Will it have the drivers?

A lot of these issues also apply to magnetic media. Magnetic media in addition needs to be refreshed. But something like 344 million drives have been shipped in the last 12 months which means that there are billions of them out there. Cloud backup services keep expanding. Backblaze has over 100,000 backup drives. And that is just one company. Consequently there will be support for magnetic media for a long time. There will be data recovery services available to recover data from the platters even if the physical drive itself fails.

So my posts about having multiple backups isn't motivated by theory, it is by actual, painful experience. I have seen way too many posts in MacRumors from people who have lost everything because they didn't have any backup.
 

WebHead

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Dec 29, 2004
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Thank you, yes those are all considerations. Nothing is perfect or guaranteed but BD-R seems the best of currently available solutions - so much so that some big data centres are moving that way for their cold storage.

I’ll still have the data on HDs (where it currently resides), I just wont be counting on that long-term.

I fully expect that when a more stable, reliable solution like holographic, quantum or molecular storage becomes available to the masses I’ll transition to that. But that may be some ways off.
 

mpainesyd

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Just reading a sci-fi novel (Dark Forest) where, faced with extinction, humanity decides that rock engravings in a cave on Pluto are the best way to save important data about our civilisation for posterity!
(hope that is not a spoiler :)
 

zorinlynx

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May 31, 2007
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Be really careful with trusting optical media for long-term storage. Treat it as an additional backup and verify them every few years.

About half of the CD-Rs I burned in the 90s so I could keep that data "forever" aren't readable anymore.

I'm extremely damn lucky I copied those CD-Rs back to my storage server in the early 00s when I finally had enough space to keep all my data online, and have backed it up since. If I had depended on those discs through today, half my data would be gone with no hope for recovery.

Storing data long-term requires custodianship; it's not something you can just archive and forget. I've learned this lesson over a couple decades of experience.
 

Fishrrman

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Feb 20, 2009
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zorin wrote:
"Be really careful with trusting optical media for long-term storage. Treat it as an additional backup and verify them every few years.
About half of the CD-Rs I burned in the 90s so I could keep that data "forever" aren't readable anymore."


Probably because the dyes used are now fading and can't "hold" the data any more.
Just like the dyes on old Ektachrome slides will fade over time.

The newer M-DISC discs don't use dyes.
Instead, they use inorganic material that can't "fade".
Thus, discs burned with this technology have a MUCH longer lifespan -- perhaps in the hundreds of years.
 

WebHead

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Dec 29, 2004
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Interesting. Any references?
Here's one from a few years back: https://www.pcworld.com/article/3019413/panasonic-to-commercialize-facebooks-blu-ray-cold-storage-systems.html



The newer M-DISC discs don't use dyes.
Instead, they use inorganic material that can't "fade".
Thus, discs burned with this technology have a MUCH longer lifespan -- perhaps in the hundreds of years.
Yes, but standard BD-Rs that use inorganic dye are still rated for several decades.
 

mpainesyd

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Nov 29, 2008
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Sydney, Australia
Remember Zip Disks - before CDs they gave us about 100MB when floppy disks of the day could store 1.4MB? A couple of years ago I decided to buy a legacy USB Zip Disk drive from ebay and to my surprise was able to read nearly all of the old Zip disks (after about 15 years) with my Mac. I found a few files/images that were worth saving but most stuff I had already moved from Windows to Mac over the years.
As several of us have pointed out above, the ability to read storage media with future computers will likely remain an issue. I was lucky in this case.
 

WebHead

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Yes, I’m hoping if there is a move to Blu-ray in data centres that will keep the technology around fir a while.