Backup and archive are not completely completely different things. While a backup serves to avoid sudden data loss, the archive should preserve important files for a long time. Of course, the same files can be put into backup and archive, but actually the archive should consist mainly from really rechargeable data.
But what data is included in the archive and in which formats? In the C’t 22/2020, we give indications in focus on long-term archiving. Collection values are especially personal documents such as the diploma thesis or photos of the family. The diploma thesis will hardly be repeated, but at least print out again – so for such documents is best suited the archive format PDF / A. Overall, open formats are better suited as a proprietare and widespread better than exotics: an image viewer for JPG files is probably still in 20 years can still be skipped, and at the moment you put the source code of an open source viewer in the archive.
Long-term storage media
But where do you save your archive? The own backup was often allowed to lie on an external hard drive, and as well, an archive is quite good – under certain conditions. Because a no longer needed hard drive from an old notebook is not suitable for long-term archiving, it is better to use a new device for that. Nevertheless, it should occasionally make sure that the data is still legible and copying it every few years to a new hard disk.
If the archive includes only a few GB, free online store is as a storage in question; for larger amounts of data you have to pay for it. An online archive has the advantage of the provider of a backup of the archive kummert. However, you have to trust that this will be still in business in 20 years.
Another possibility is the almost forgotten optical media today. Although blu-ray co. Only a lifespan of maybe 20 years, but the M-disc should hold much more long; the manufacturer promises 1000 years. We have burned a hundred GB and looked, as faultless the data has landed on the slices.
But even if the archive is saved, the work is unfortunately not over: professional users copy their archives every few years to a new medium. You have to consider that as a private channel, and above all you should have a backup of the archive. It is best to do that if you use at least two of the three possibilities mentioned for your archive. This is on the safe side.