On Mon, Jan 16, 2023 at 9:48 PM Fred Cisin via cctalk <cctalk@classiccmp.org> wrote:
> > What about M-DISC DVDs and BluRays? Archival grade, not susceptible > to magnetism or EMP. I think BluRay discs are made of a harder material > than DVDs and don’t scratch as easily. > > I have had magnetic, AND optical media that have "gone bad". > > I am interested in whatever media are more likely to still be readable in > a few decades. > LTO tape, properly stored, is advertised as having a 30 year lifetime. Of course tape isn't particularly convenient for ad-hoc access so my archival strategy is to dump things to a file server with a *lot* of disk space (RAID1 or RAID10, not RAID0 or RAID4/RAID5), then regularly back up that server to LTO tape. The current generation (LTO8) is very expensive so I use LTO4 and LTO6 tapes which are comparatively very affordable. The data doesn't tend to change but taking repeated backups anyway helps to ensure that silent bit-rot on the hard disks is detected early enough to be correctible. Having backups on tape also has the advantage that the tapes are easily moved off-site, so a fire or other such disaster won't take out my server and my backups both at once. There is another significant advantage to focusing on a backup strategy as opposed to an archival strategy -- I don't need to worry about tapes I made today being readable decades in the future (i.e. I don't need to worry about keeping legacy tape drives running). The file server is the "archive" and I only *need* to be able to read the tapes I made last year or last month. If a tape drive fails I can just get another one, and if they become hard to get there's nothing stopping me from upgrading to something newer with better availability (i.e. I don't have a library of old media that I need to be able to read forever). The disadvantage of course is that a file server isn't something you can reasonably put in storage for future generations to access. This strategy really only works if the file server is accessed frequently so that accessibility/compatibility issues can be fixed incrementally as they happen (while they are still easily addressed using current/recent technology). -ken
