External DVD/CD

[ab1jx]

I once did a quick price comparison and just buying hard drives compared well with removables.  2 TB is around $55 https://www.google.com/search?psb=1&tbm=...kFegQIARAS  3.5 inch goes a little bigger and cheaper per terabyte.  I think the internet archive (archive.org aka the wayback machine) found it was most cost-effective, or did years ago.  2 TB seems to be the max size of a laptop (2.5 inch) hard drive.

You can get 2 TB of nvme SSD for around $225. https://www.google.com/search?psb=1&tbm=...kFegQIARAS

But yeah, there's at least a theoretical advantage to mostly indestructible offline storage.  And if 1 fails most of them are probably OK.  2 TB is 465 DVDs.  I was buying them on sale at Staples, Sony only, for $20/100 pack around 2009, so that was $93 for 2 TB.  And 465 DVDs is a lot of plastic.  I see advantages to both methods.
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I just wrote this and tested it.  apt-get install par2, then save this as something and chmod +x it.

Code:

#!/bin/bash
# Makes par2 files for all files in a dir with extension on cmd line
# Use like parall doc, or parall jpg (no period)
shopt -s nullglob
for f in *.$1
do
/usr/bin/nice -n19 par2 create -r10 $f
done
# make a pars dir and put all the clutter in there - copy back to use
mkdir -p pars
mv *.par2 pars

Par2 files provide redundancy and work a little like a RAID.  If some portion of your material goes bad, you can recover by having enough par files.  Read the part2 man page after you install it, this is set for 10% redundancy, you might want more like 30-40%.  They take up space but they're like insurance.  I wrote this for making par files for directories full of mkv files but you could use it on any file type. This makes a set of par files for each mkv file because they're each 300 mb or so, you could easily make a set for a directory full of mixed files. Filenames are based on the input file names so nothing gets clobbered.