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Re: is it possible to add a secondary disk to an existing debian systems and install programs to the secondary disk

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On Sat, 27 Feb 2021 15:19:39 +0300
Semih Ozlem <semihozlemlinuxuser@gmail.com> wrote:

> Should I then be suspicious of a possible attack on the system in
> case the system fails, if both debian and ubuntu are fairly stable?
> The usb flash drives themselves are still functional in the sense
> that I can view the files in them after plugging them in. I backed up
> the data on them. But when I try to boot from 64 gb usb flash disks
> (one with ubuntu 18 04 the other debian 10 point something installed
> on them) the boot process does not complete and the login screen does
> not appear. The two recovery modes (I guess those are the snapshots
> no?) do not finish booting either.
> 

There are parts of the system that aren't files, that you're not
checking. Grub writes a bootloader to the MBR of a normal drive, but a
USB stick may not have a partition structure, in which case the
bootloader will be written to the start of the drive. If this gets
damaged, you can use a low-level disc utility to copy it out and check
it, but the easier way is to boot from a rescue USB stick, then try to
chroot into the faulty OS and update grub from there, which will
rewrite the bootloader.

The recovery mode is grub itself plus a number of utilities and
drivers. From here, you can generally find drives and partitions, mount
partitions and edit files if you can see what's wrong. It sounds like
the early booting part of grub is itself damaged in your case.

And no, LVM snapshots are nothing to do with boot or recovery
processes, they are a means of freezing the files of an installed
operating system so that a proper backup can be made while still
allowing the system to run. Changes to files are stored in a buffer
area, and read from there, then when the backup is finished the
snapshot can be closed and the file changes will be merged back to the
real file locations. The system will obviously run more slowly while
the snapshot is open, but that may be far better than shutting it down
for an offline backup.

If you try to make an online backup without using this method, some
files will change during the backup, meaning that the set of files that
are written to the backup may not be consistent enough to run properly
as a complete system. Certainly database daemons must be stopped, as
well as anything else outside the core OS that makes persistent changes
to files (e.g. a mail server). Most changing files are temporary, so it
is often possible to get away with an online backup without a snapshot,
particularly if you only ever need to restore single files or
directories. Cloning a full working OS is generally best done offline,
unless you have LVM plus space for the buffer.

-- 
Joe

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is it possible to add a secondary disk to an existing debian systems  and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-22 21:10 +0100
  Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Brian <ad44@cityscape.co.uk> - 2021-02-22 21:30 +0100
    Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-22 22:00 +0100
      Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Greg Wooledge <greg@wooledge.org> - 2021-02-22 22:20 +0100
        Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-22 22:40 +0100
          Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk "Andrew M.A. Cater" <amacater@einval.com> - 2021-02-22 23:20 +0100
          Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk David <bouncingcats@gmail.com> - 2021-02-22 23:20 +0100
            Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-23 00:10 +0100
              Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk David <bouncingcats@gmail.com> - 2021-02-23 00:20 +0100
              Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk "James H. H. Lampert" <jamesl@touchtonecorp.com> - 2021-02-23 17:20 +0100
              Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Nicholas Geovanis <nickgeovanis@gmail.com> - 2021-02-23 17:20 +0100
                Re: is it possible to add a secondary disk to an existing debian systems and install programs to the secondary disk rhkramer@gmail.com - 2021-02-23 17:40 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Nicholas Geovanis <nickgeovanis@gmail.com> - 2021-02-23 18:00 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Joe <joe@jretrading.com> - 2021-02-23 18:20 +0100
          Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Andrei POPESCU <andreimpopescu@gmail.com> - 2021-02-23 09:30 +0100
            Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Celejar <celejar@gmail.com> - 2021-02-25 15:50 +0100
              Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk <tomas@tuxteam.de> - 2021-02-25 16:00 +0100
              Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk IL Ka <kazakevichilya@gmail.com> - 2021-02-25 16:00 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Celejar <celejar@gmail.com> - 2021-02-25 16:20 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk IL Ka <kazakevichilya@gmail.com> - 2021-02-25 16:30 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk The Wanderer <wanderer@fastmail.fm> - 2021-02-25 16:50 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Greg Wooledge <greg@wooledge.org> - 2021-02-25 17:00 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk The Wanderer <wanderer@fastmail.fm> - 2021-02-25 17:10 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk IL Ka <kazakevichilya@gmail.com> - 2021-02-25 17:00 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Celejar <celejar@gmail.com> - 2021-02-25 16:50 +0100
  Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk David Christensen <dpchrist@holgerdanske.com> - 2021-02-23 04:10 +0100
    Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk martin f krafft <madduck@debian.org> - 2021-02-23 11:40 +0100
      Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-26 07:00 +0100
        Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Charles Curley <charlescurley@charlescurley.com> - 2021-02-26 08:00 +0100
          Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-26 08:40 +0100
            Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Greg Wooledge <greg@wooledge.org> - 2021-02-26 13:30 +0100
        Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk David <bouncingcats@gmail.com> - 2021-02-26 11:00 +0100
          Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Charles Curley <charlescurley@charlescurley.com> - 2021-02-26 18:30 +0100
            Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Greg Wooledge <greg@wooledge.org> - 2021-02-26 18:50 +0100
              Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-27 09:40 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-27 09:40 +0100
                About keeping a Debian installation happy [was: is it possible to  add a secondary disk to an existing debian] systems and install programs to  the secondary disk <tomas@tuxteam.de> - 2021-02-27 10:20 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Joe <joe@jretrading.com> - 2021-02-27 10:10 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-27 13:30 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Semih Ozlem <semihozlemlinuxuser@gmail.com> - 2021-02-27 13:30 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk "Andrew M.A. Cater" <amacater@einval.com> - 2021-02-27 14:50 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk Joe <joe@jretrading.com> - 2021-02-27 15:20 +0100
                Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk David Wright <deblis@lionunicorn.co.uk> - 2021-03-01 01:40 +0100
        Re: is it possible to add a secondary disk to an existing debian  systems and install programs to the secondary disk martin f krafft <madduck@debian.org> - 2021-02-27 09:30 +0100

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