[geeks] Cheap/reliable backup?

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On Mon, Dec 02, 2013 at 01:26:46PM -0500, Mouse wrote:
> > Is there a cheap/reliable way to backup data from a disk?
> 
> Insufficient information.  Why do you want backups?

So I don't lose all my data! I have a lot of static data that I'd like to be
able to know won't ever get lost due to a hardware failure. If it did get
lost it would be very hard/impossible to replace.

>  What OS?

OS-independent data. Often moved between various boxes.

> What other tradeoffs?

Cheap as possible without risking the data!

> 
> There are three purposes I've identified that backups serve:
> 
> (1) Mistake recovery: "Oops, I didn't mean to delete that."
> (2) Historical queries: "This worked last May, what was here then?"
> (3) Failure recovery: "Oh $h1+, the disk just died."

I have solved (1) in the past with period rsync-age. It actually got me out
of two real screwups. I still think it's a good idea.

I have mostly solved (2) with fossil (source control but works for
anything). The only problem is I have to start keeping the fossil repo out
of tree because you can't recover a directory when the repo was *in* the
directory that just went away.

I'm trying to solve (3). I've had mixed results with consumer drives. Some
seem to work forever, others seem to die at the worst time possible. I
really don't like the idea of trusting a disk to back up another disk unless
the backup disk is better quality than the source, and that can get very
expensive fast over here and doesn't seem like a good long-term solution
anyway. And it's still spinning hardware so it will eventually fail. It
seems wrong to get into disk chasing that never ends. I really want the
stuff off disk and onto something else.

Local price point: Caviar Blue 1T drives are 100 USD each, Blacks go
for 125. Don't know what you guys are paying. Prices have come down a lot,
for a while after the floods they were about 300 dollars each for a long time.

> > I don't usually hear about the latest tech stuff for a decade or so
> > but it seems to me the only thing people are doing to backup their
> > data is mirroring it (not exactly a backup but good if one disk
> > suddenly fails)
> 
> How is it not a backup?  It's mostly good for (3), and it's what I do
> for backups.  If you periodically swap out one backup drive and swap in
> another, it can serve for (1) and (2) too.

It's certainly not good for (1) although that doesn't happen to me much, if
ever. In fact I've been living with it (mirroring) for awhile and I survived
two disk failures with no loss. I just don't want to take a chance that it
will always work, because it mostly depends on software and that is seldom
bug free (enough). And I don't like the idea of disk-chasing, where stuff
goes from disk to disk and you hope it never gets lost, etc. I'm looking for
more of an archival mode if something for that exists beside that 2 billion
square mile black hole in Utah...

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