Unanticipated time and costs for full recovery

[Craig <craig.lists@subs4.sitnominedigna.com>]

Hi there,

I've completely rewritten this message twice because the first version
sounded too whiney and the second version is stale having sat unsent
for most of two months. This one probably will probably sound whiney as
well, but just imagine then what the first version sounded like! This
version also includes a suggestion, as well as my question.

I've never done a full data recovery before because I never thought I'd
be stupid enough to need to. Apparently I'm wrong. A single file here
and there? Sure, but not my whole collection of data created and saved
over the course of forty-five odd years. (Thank the gods I backed it up
despite knowing I was so smart.) But the reason I need to do a full
recovery is not because my house burned down or because that experiment
of swimming with my hard drive didn't work, but because LUKS decided
that my password didn't work any more. Imagine that! If you want to
cure someone of using encryption to save their data, just decide to
deny their password that was working over multiple operating systems
every day for over a decade. Now I'm in the class of people that
"claim" they didn't lose their password, but we all know the truth,
nudge nudge, wink wink.

But I am annoyed because I didn't think I'd have to re-mortgage the
house that didn't burn down to recover my ~350 GB of data. (I had
chosen not to back-up some stuff because it wasn't "vital", but I'm
going to miss that stuff anyway that I wasn't willing to pay for,
because I knew that when my house burned down I'd just be thankful I
got the "vital" stuff back.) I suppose not knowing how much my recovery
would cost is my own fault, because obviously 350 GB x $0.25/GB is a
little more than the $55 that was in my account after recently topping
it up. So my bad that the recovery failed after 92 hours on a cable
connection when, shock of all shocks, my balance ran out.

But 92 hours for just *some* of my data?! (That's just under four full
sleeps, in case that's not obvious.) I obviously didn't get all 350 GB,
but even if the last byte managed to slip through just as my balance
hit zero at the 92-hour mark, that's a download rate of 350 GB per 92
hours, or 3.8 GB per hour ... and *significantly* less than 350 GB got
through so, of course, the *rate* was *significantly* slower. Although
I don't know enough to write or understand formulae like "O(N log N + N
· M log M)", I know that 3.8 GB per hour is *significantly* slower than
the download speed I just tested/measured of 93 Mbps. (I feel the need
to state that I know the difference between a bit and a byte.)

Bottom line is I'm going to have to re-start my recovery based on
actually thinking (what  a concept!) about how much it will cost to get
350 GB back. I will add double that amount to my account, and then add
another $55 for what I usually pay in a month. Hopefully that will more
than cover it.

To address the time for recovery problem -- about which I was vaguely
aware before, but not acutely as I am now -- I will use the apparently
only somewhat reasonable alternative out there, which seems to be
Redsnapper. I just never thought about recovering *all* my data
because, as I said, I'm way too smart to lose all my data.

QUESTION

My only question at this point, having got the background out of my
system, is this: Is it possible to restart my back-up recovery from the
point at which it failed so that I don't have to thrown out the
approximately $55 I've already spent bringing down the data I have
already paid to bring down? (Pardon my redundancy.) Or do I have to
start again from scratch and waste/spend that $55 again?

-----

Thanks.


Craig


P.S.: A code suggestion: The command to recover a full back-up is,
"tarsnap -x -f ARCHIVE-NAME", while the command to recover a single
file or directory is, "tarsnap -x -f ARCHIVE-NAME path/to/file.ext".
While I don't usually suggest or encourage hand-holding, it seems to me
that if the former command is used "tarsnap" should do one of two
things: (1) Pause the execution to ask, "Are you sure your account
balance will support recovering the full archive at $0.25 per GB?", to
which the user should respond y/n after checking their account (and, if
necessary, topping it up); or, (2), if "tarsnap" has access to the
user's balance it could make a more intelligent judgement. It has
occurred to me in the past that "tarsnap" having access to an account's
balance (for option 2) would be a good idea for the same reason that
"your balance is a week away from zero" emails are sent; I've seen
complaints from people saying that they didn't know their balance was
approaching zero because (for some reason) they don't read messages
sent to their account's email address (which seems bizarre), but if
they read their messages sent by their cron job they might see a
message like, "Your balance is near zero." Just an idea.