On Wednesday 25 July 2018 16:15:03 Mark Morgan Lloyd wrote:

> On 25/07/18 19:00, Gene Heskett wrote:
> > On Wednesday 25 July 2018 07:22:46 Mark Morgan Lloyd wrote:
> >
> > I have not been successfull at "make pdfdocs", it hits something it
> > doesn't like in the chapter on networking, not finding a file that
> > is (or was) installed since this is now armbian, and which an
> > apt-file find pdftex returns 262 versions of it as available. But
> > which is the correct version? $64k question, that. Lots of stuff
> > missing for make pdfdocs, not working yet and apt has drug in close
> > to a gigabyte of stuff.  And apt can't find half of what it wants
> > even then. But it may have succeeded, now installing okteta, and
> > okular another 150 megs of dependencies that pulls in for each.
>
> That's something I've never tried I'm afraid, and I suspect that most
> people use an online one.
>
> However if you really do need to do that I suggest looking at the
> manpage for make, since knowing exactly what command was being run
> would probably help you a lot.
>
> > But lastly, because I've made some real progress, I need to make an
> > image backup of / but without the contents of /media/slash because
> > that is where I'll put the "backup". How the heck do I do that?  And
> > what command is used to image the sd to the eMMC?  Then I'll see if
> > it will boot from the eMMC, then have make make the debs.  Seems
> > like a  logical order anyway...
>
> Really depends what you mean by an "image backup". I do a lot of stuff
> using "ye olde traditional" dd, either between devices or more often
> making an image of the entire device (i.e. including partition table
> etc.) to a file and manipulate it there (e.g. by deleting a directory
> tree /after/ the data has been copied).
>
> However when using something like dd there's a major problem: you
> either want the storage medium to be removed so you can copy the
> filesystems offline, or you need to shut every possible piece of
> running software down (including things like your SSH daemon) so that
> nothing's writing to the disc when you're trying to copy it. Needless
> to say the same considerations apply when using dd to do a
> sector-by-sector copy from one device to another.
>
> That would normally be done by putting the system into single user
> mode, and traditionally that was done using something like the 
> telinit 1 command... and it was that that I complained about at the
> start of this thread, since I suspect it was responsible for killing
> an SDCard in a TinkerBoard.
>
> There are still ways of working round that sort of problem. For
> example, you can copy an entire device using dd to capture boot
> segments and partition layout, inspect and recreate the filesystems
> using mkfs, then use [something] to copy files one at a time into the
> new filesystems taking care that some bootloaders need a wakeup call
> when a file moves.
>
> As far as "something" is concerned:
>
> dd: Sector-by-sector copy between devices and files.
> tar: Good ol' archiver, with directory-exclude etc. options.
> netpipes: Do a tar or dd over the LAN.
> rsync: File-by-file copy over LAN.
> rdist: Ditto, less well-known but with some good points.

I'll have to look at that. I need dd like copies, but I don't 
want /media/slash to be anything but an empty dir in the image it makes.

> parted: Resize a partition.
> resize2fs: Resize a filesystem contained in a partition.
>
> So in combination, a fairly common use case would be to dd an entire
> device to a file, resize2fs the final filesystem to its minimum size,
> parted to reduce the final partition to its minimum size, dd to put
> the file onto a new device (noting that even if the size is nominally
> the same, it's common for it to be smaller by a piffling few 100s of
> Mb hence the palaver of resizing) and finally expand the final
> partition and its included filesystem to fit.
>
> I've done rather a lot of that sort of thing, it's very much "old
> school". And like everybody else, on at least one occasion I've got
> the dd parameters wrong and roached something I really wanted to keep.

Got the t-shirt and wore it out myself. ;-) Sometimes the recovery has 
been a cast iron bitch. I'm almost afraid to putz with the r-pi-3b as 
its working better these days. Now if I could just figure out how to fix 
the ssh logins. I think I'll go run synaptic and reinstall that ssh kit.

-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

Reply via email to