[QUOTE=retina;547143]:tu: Yes!

Offline, unplugged, rotated. [/QUOTE]
You missed 2 more things.

Off site. If I burn down your evil lair, can you restart? If there is a $NATURALDISASTER in your region, can you restart?

Differential media types and connection interfaces. An SSD may have a shorter or longer stability than a burned DVD or platter spinner. Many people with ZIP drives are finding out that they are not so useful anymore. (NASA had to scrounge to find obsolete tape recorders to get back to first generation data.)

[QUOTE=Uncwilly;547154]You missed 2 more things.[/QUOTE]Okay, thanks.[QUOTE=Uncwilly;547154]Off site. If I burn down your evil lair, can you restart? If there is a $NATURALDISASTER in your region, can you restart?[/QUOTE]I'm good for this type of problem. Thanks for showing concern for my operations.[QUOTE=Uncwilly;547154]Differential media types and connection interfaces. An SSD may have a shorter or longer stability than a burned DVD or platter spinner. Many people with ZIP drives are finding out that they are not so useful anymore. (NASA had to scrounge to find obsolete tape recorders to get back to first generation data.)[/QUOTE]This is tricky. I just go for regular replacement during the rotation. New media is added and old media is retired.

A homogeneous media type might be susceptible to a class failure. For example: A strong EMP might erase all magnetic media, if they are all stored in close proximity to the source. So geographical separation is useful here, unless one is concerned about a [url=https://en.wikipedia.org/wiki/Magnetar#Magnetic_field]magnetar coming within 200,000 km of the Earth[/url].

Some folks use paid "cloud" services for offsite and consider it a different physical format.

[QUOTE=Uncwilly;547197]Some folks use paid "cloud" services for offsite and consider it a different physical format.[/QUOTE]Indeed. I don't use it but do consider it as such.

However, such usage opens up another can of worms. Information not under your direct control is not under your control. A banal truism perhaps, but it does rather imply that if you can't stop the service provider denying you that service in future. It also implies that the service provider can read, write, delete, copy and re-distribute your data. Crypto can make readability unimportant but it (a) needs care and attention from you, (b) can make modification detectable and (c) does essentially nothing else.

As always, answer the question "what is your threat model" before implementing specific procedures.

[QUOTE=Uncwilly;547197]Some folks use paid "cloud" services for offsite and consider it a different physical format.[/QUOTE]Those folks need to ask their provider what they use. More likely would be the advantages of physical separation, rather than different media. I would imagine most places that have large data requirements are using magnetic options, either tape or HDD (or both). DVDs are too tiny and/or expensive to be realistic for a "cloud" setup. Same for SSDs I expect. What else is there? Papyrus? One million line printers churning out your backups!

[QUOTE=retina;547209]What else is there?[/QUOTE]
There's a fun way of backing up your genome...

:direction:

Isn't NAS about (controlling) file availability on a network, not a backup solution?

[QUOTE=paulunderwood;547214]Isn't NAS about (controlling) file availability on a network, not a backup solution?[/QUOTE][QUOTE=Prime95;547104]I'm thinking of building a simple NAS for my network, [b]mainly for backups[/b].[/QUOTE]:razz:[QUOTE=retina;547132]I also don't view NAS as a backup solution in most cases either.[/QUOTE]

[QUOTE=retina;547209] One million line printers churning out your backups![/QUOTE]

What about a series of mercury delay line tubes?

[QUOTE=paulunderwood;547216]What about a series of mercury delay line tubes?[/QUOTE]Stone tablets.

If it was good enough for my great[sup]n[/sup]-grandfather then it should be good enough for me.

[QUOTE=Uncwilly;547197]Some folks use paid "cloud" services for offsite and consider it a different physical format.[/QUOTE]
Am I doing it right?