[GTALUG] Backups for files

[Lennart Sorensen]

On Thu, Nov 05, 2015 at 11:47:15AM -0500, D. Hugh Redelmeier wrote:
> | From: o1bigtenor <o1bigtenor at gmail.com>
> 
> | Looking at backing up a little less than 300 GB of files. Want to do
> | one copy to 25 GB Bluray discs.
> 
> I think about this but don't act on it.
> 
> I don't know the perfect solution.  I've had ALL kinds of media go bad
> or unreadable due to loss of technology.
> 
> The best bet (and I don't do this) is to have multiple copies on
> multiple media.  Actively backed up (i.e. in a rolling repeated
> process, onto new media as they becomes available).  Physically
> separated (so one fire, flood, or war doesn't take it out).
> 
> All media age in some ways, not all known ahead of time.
> 
> I've had CD's physically destroyed by plasticizer from the window on
> the paper sleeve they were stored in.  It took a number of years.
> Threats can come from out of left field.
> 
> The lifetime of media seem to have a LIFO nature.  Newer stuff is
> often more delicate (and made obsolete sooner).
> 
> - stone tablets came first and outlast most of their successors
> 
> ...
> 
> - paper from before ~1850 last a long long time
> 
> - later paper (from wood pulp) last a long time (but less than older paper).
>   I have books that I bought new that are deteriorating from the acid
>   in the paper.
> 
> - punch cards and paper tape seem to last indefinitely (I have modest amounts)
>   and I can read them by hand.  I think I could build my own reader if
>   I felt the urge.
> 
> - 9-track tapes (I have some backups on them) aren't useful any
>   longer because the drives are expensive and rare.  Probably the
>   recordings have decayed but I have no way of finding out.
> 
> - 8", 5.25", 3.25" floppies are starting to fall off the edge.
> 
> - LASER disks and magneto-optical disks appear to be gone.
> 
> - MFM and RLL disks are no longer supported.
> 
> - SCSI and (p)ATA disks are all but gone.
> 
> But maybe your information will be unimportant before any of this
> kicks in.
> 
> There are DVD's that claim to have very long lifetimes.  They might be
> worth a shot. <https://en.wikipedia.org/wiki/M-DISC>
> 
> Blu-rays seem to have little takeup for data.  I don't even know if
> Linux has software to master them.  I would avoid them.  (I bought a
> Blu-ray burner but have never used it for Blu-rays.  It can also burn
> M-Discs but I haven't used that feature yet.)

Mastering bluray videos that will work on a player with menus, I have
no idea.  But putting data on them is simple.  I just generate a 23GB
file, format it UDF and loop mount it, put my files in, then unmount
and use growisofs to write the file as an image to the buray write.
Mounts perfectly and reads everywhere.  I suspect you could even use
the udf write support in the kernel to write directly to the bluray disc
but I haven't tried that method yet.

> USB flash-memory sticks are very convenient.  I have no confidence
> that their lifetime will be long and reliable.  Anyone know?
> 
> For our most important records we still keep paper.

-- 
Len Sorensen