On Thursday 26 July 2018 12:51:07 Mark Morgan Lloyd wrote: > On 26/07/18 16:15, Gene Heskett wrote: > > On Thursday 26 July 2018 03:06:31 Mark Morgan Lloyd wrote: > >> On 25/07/18 21:30, Gene Heskett wrote: > >>> On Wednesday 25 July 2018 16:15:03 Mark Morgan Lloyd wrote: > >>>> 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. > >> > >> dd to a file, then use losetup -f -P to make the partitions in > >> that file mountable, mount the appropriate one and delete the stuff > >> you don't want. > > > > Wouldn't the file, if put on /media/slash, it seems dd would > > include /media/slash in that file, and the result even if it didn't > > get into a recursion forever loop, would still be around 10GB bigger > > than media//slash, and it already has some stuff on it: > > I was assuming that you weren't trying to dd to something on the same > physical device... which would be highly inadvisable if not impossible > since you need to put what you're copying from into a quiescent state > (i.e. single user or as Adam pointed out fsfreeze. > Not from-to the same device, / is a 32Gb u-sd card its currently booting from, and /media/slash is /dev/sda3, hooked up by a usb-3<->sata adapter plugged into a usb-2 port. But the /media mount point is in the u-sd file structure. Would dd follow that into the files that are there on the SSD?
There is supposed to be a flag that can make the pi-3b boot from an attached hard drive, but I have never had the command to flip it, work always a permissions error or something. Early pi's don't have it? > So either get another temporary device and connect it via USB, or use > dd+netpipes to copy the device onto a different system over the LAN. or sshfs. I don't currently have it setup so root can use it though, just me is all. > > I need dd like to preserve the file addresses in /boot as I've read > > they are expected to be at fixed addresses with this boot method. > > There's usually something that can't easily be moved, unless there's a > loader in ROM with enough smarts to be able to drive a FAT (etc.) > filesystem. Which I don't believe the pi-3b has. > > > Maybe it would be best if I used the resize utility to resize the / > > to just over whats used. I've made a copy of /home/pi/linuxcnc, so I > > at least have the codes I've already written backed up locally. > > But you'll still need to unmount / or at the very least go into > single-user mode or freeze it before you can do anything like that. > > > And I've not been able to find, but haven't looked online, a man > > page for rdist. Now have, but bears a re-read, its nothing like a > > dd. > > As I said above, rdist is comparable with rsync. So I'd best pull that sd card, put it in a reader and dd it to a file, then dd that file back to a 64 Gb sd just to make a backup copy? I'll need a few more 64Gb's just to have working room. Thanks, Mark. -- 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>
