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Re: Upgrading with a low data cap

On 10/7/18, Richard Owlett <rowlett@cloud85.net> wrote:
> All my machines have use Stretch DVD1 for installation.
> I have a low monthly data cap - currently at my limit.
> One machine has an apt-get update and upgrade with the addition of some
> packages not on DVD1.
> I've not intentionally deleted any cached files.
> Is it possible to use the cached data on another machine?
> What should I be reading?

I don't know if I'm understanding the question correctly. It sounds
like one possibility is like where *I* bind my massive ~20GB+ hoard of
dotDebs to my /var/cache/apt/archives. As much as I debootstrap over
and over, that works fabulously *for me* on dialup.

My method is:

mount -B /path/to/archive/hoard /var/cache/apt/archives

The hoards are housed as child directories on various partitions on
miscellaneous hard drives.

I used to employ symlink instead of bind ("-B" or "--bind"). The
symlink route *appeared* to work then one day I figured out that route
was the culprit in the "I HAVE NO NAME!" identity crisis that my root
user was yelling about after chroot'ing into debootstraps. I've never
stopped to research the technical difference there, but there *is* one
because root's been a happy little name-bearing camper ever since I
made that change. :)

There is a "danger" in going the bind route. It's something I learned
on the fly. If you delete a whole operating system off of a partition
while archives are still *symlinked*, your hoard stays safe in place.
I just tested that one last time to make sure, and *mine* does stay in

If you delete an entire operating system while /var/cache/apt/archives
is still live via "mount --bind"....

Kiss your absolute entire hoard goodbye even though it's housed one
step off from the operating system you're deleting. *oops!*

Something I also learned after having mistyped something at some point
is that you can bind more than one directory to that archives path. I
don't know if that's technically sound, but mount doesn't complain and
it works!

My various hoards are named things like "apt-bind", "apt-etc", and
"apt-i386". I also tested that just for this and was able to see the
contents of apt-bind and apt-etc displayed at the same time under
archives when using "mount -B" for both.

It doesn't work like that for symlink. *For me*, symlink instead
throws a (basically useless) secondary symlink inside of archives for
each additional directory I might try to symlink after the first, raw,
original symlink is created. It's something that makes sense as part
of symlink's design. It just doesn't work for painlessly trying to
bring a bunch of hoarded archive files together in one place.

Again, I don't know how technically "sound" my "mount -B" method is
over time, especially when binding more than one directory into the
same place. I *do* know that it has been working very painlessly *for
me* for about 8 months to a year now. If you do a lot of temporary
sandbox playing with things like debootstrap'ing and test-driving new
operating systems all the time, you just GOTTA remember to unmount
before you wipe a partition clean else *OUCH*. :)

Cindy :)
Cindy-Sue Causey
Talking Rock, Pickens County, Georgia, USA

* runs with duct tape *

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