Trying to describe the specifics of my system in detail is a bit over the top for the time I have at hand. But I'll give you the basis of the system:
Digital archiving is based upon three primary notions:
- duplication
- media migration
- policy
Unlike film and analog processes, you can precisely copy, with bit for bit verification, any image file an infinite number of times. That's a baseline fact that you can just accept as an assumption.
As storage devices and file systems are improved and expanded over time, you migrate digital image files from your current one to the next one that you adopt. Digital image formats are pretty stable now, I expect DNG, JPEG and TIFF will be with us for many many years to come, so there's little format translation needed anymore as a part of migration. In general, I've found that buying enough of a current storage solution to handle three years worth of data is a good saddle point on costs vs risks. When you've filled that storage solution, you can usually buy the next one with twice the capacity at the same or lower price as the old one.
So it then comes down to policy. I maintain a working copy of my image files along with two identical and independent backup copies, locally, and one off-site copy. The likelihood that all three local repositories are going to go unrecoverable simultaneously is very low.
Upon arriving at my image processing workstation with new work, the new work is organized and imported into the system according to my pre-defined schema and then the backup program is run so it is replicated to the two archive repositories. The same applies whenever I do a rendering session: after the rendering session, I immediately fire off the backup system and all the changes are duplicated into the archives. Once a month, I swap one of the archives with a duplicated archive stored off-site, and the one I bring back is updated to reflect the current state of the data.
Everything else is an implementation detail. The key thing is to remember that digital archiving is an active process of duplication and migration with policy, not a matter of how long media will survive. Analog archiving is entirely concerned with media permanence and catalog maintenance, by comparison.
G