Re: Resize a disk image from 32G to 4G or copy u-boot?

[grumpy@mailfence.com]

On Wed, 25 Mar 2020, Gene Heskett wrote:

> On Wednesday 25 March 2020 08:51:17 grumpy@mailfence.com wrote:
>
> > On Wed, 25 Mar 2020, Gene Heskett wrote:
> > > On Wednesday 25 March 2020 04:18:20 Andrei POPESCU wrote:
> > > > On Ma, 24 mar 20, 19:12:46, Gene Heskett wrote:
> > > > > And nothing so far, and I have been watching, in the way of
> > > > > reducing a filesystem to only the actual size occupied. Then it
> > > > > can be backed up with dd and recovered, rewritten by dd, at a
> > > > > reasonable size for storage.  And re-expanded to fit the media it
> > > > > finds.
> > > >
> > > > You could do this with the 'sparse' option of dd (you might need to
> > > > fill the partition with a file containing only zeroes first).
> > > >
> > > > The resulting file must be handled with care as many tools (cp,
> > > > rsync) will un-sparse it by default, as will writing it to a
> > > > filesystem without support for sparse files (tar it first).
> > > >
> > > > To see the actual size with ls you will have to use -s/--size.
> > > >
> > > > > All of my attempts to do that with dd alone have been thwarted by
> > > > > the fact that I have yet to find two u-sd's marked as such and
> > > > > such a capacity, that actually were the same size.
> > > >
> > > > Just create the partitions slightly smaller than the size of the SD
> > > > card.
> > >
> > > I've also considered that, but then you risk losing the gpt tables
> > > and it all disappears in the cloud of blue smoke being emmited from
> > > ones ears.
> > >
> > > BTDT at least twice on arm systems. The distro folks have it and use
> > > it to make an install image of 5 gigs, unpacks to 7 or 8G and which
> > > can then be auto expanded on the first reboot to fill the card, so
> > > they know how to do it, why can't the user make backups from a
> > > deployed well running system that could be put on a fresh u-sd card
> > > and treated exactly the same for recovery purposes?
> >
> > could you not just dd to a file and then manipulate that file to suit
> > you but i would never dd a running system
>
> Amanda has very occassional problems with that as all its backups are
> from a live system.


doing backups of files and creating an image are apples and oranges
it sounded like you wanted an image that could be redeployed
if you create an image and save a copy on your backup server
exclude it from your amanda backup since it will never change