GB/in^3

[ilkhan]

Ignoring GB/$, which would be more dense for a given volume (say you wanted to store data in a safe deposit box), DVD-DLs, (500GB?) 2.5" HDDs, or (1TiB) 3.5" HDDs? (Connection medium doesnt matter, controller, etc. This would be for off site archive)

 

[hjreggel]

I would recommend 2.5" harddisks. You can get 500GB at 12.5mm height, and the disks are designed to be carried around - unlike 3.5" harddisks.

I would not trust DVD DL media, because it can be hard enough to read out a single layer media, so I would not take the risk of having two layers.

 

[wildfire99]

If you can afford it, an LTO Ultrium (4). HP has their 1.6TB drives coming out real soon. Each tape is 4.5"x4.38"x1.06". After that, the obvious answer by eyeballing it is the 1TB HDDs. Maybe you could get the notebook drives to fit better, but you're still dealing with playing games with swapping drives and handling them (ESD).

A whole 100pc spindle of 8GB DVD's isn't even 1TB and it's taking up about the space of 8, 3.5" HDDs. Even if you were insane and doing it by hand, a similarly-sized spindle of 25GB BD's would be 2.5TB, in the space of 8TB for the drives.

Depending on how much you're backing up, you might not have any other sane recourse other than a server box full of 1TB drives. I don't even want to think of how long it would take to back all that up.