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Re: Restore backup to KVM

From Reco <recoverym4n@gmail.com>
Newsgroups linux.debian.user
Subject Re: Restore backup to KVM
Date 2017-09-30 13:10 +0200
Message-ID <uvnOF-3lm-1@gated-at.bofh.it> (permalink)
References (5 earlier) <uueu6-7gi-13@gated-at.bofh.it> <uujk6-2b5-7@gated-at.bofh.it> <uunQK-5FA-15@gated-at.bofh.it> <uuAXD-5v7-1@gated-at.bofh.it> <uuVfH-1vc-7@gated-at.bofh.it>
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	Hi.

On Fri, Sep 29, 2017 at 06:30:21AM +0200, solitone wrote:
> On 28/09/17 08:58, Reco wrote:
> > It's initrd that first tries to mount tmpfs filesystems on /root (and
> > fails), and only *then* mounts your root filesystem to /root (with the
> > intention to switch to it as /).

> Also, I don't understand why it needs to mount the root filesystem to /root.

So, I did some tests. Results are somewhat unexpected.

First things first, either I'm missing something, or MODULES=most does
not work as advertised. It did not put "all harddrive drivers" into
initrd for me.

Second, once I convinced update-initramfs to put missing kernel modules
into initrd, QEMU booted successfully with "init=/bin/bash".

If I understand what's written in /usr/share/initramfs-tools/script
correctly, the way it should work is the following:

1) Unpack initrd, load kernel modules, etc.

2) Mount root filesystem to /root (and that's initrd's /root!).

3) Re-mount /dev into /root/dev (that's init-bootom/udev, and that's
where it fails for you).

4) Mount procfs, sysfs (and several others) into appropriate directories
of /root.

5) Mount everything appropriate from /etc/fstab.

6) Execute pivot_root(8) to switch root filesystem, start init.

Therefore the next thing I have to suspect is that your backup misses
/dev directory (possibly /proc and /sys). The contents for those are
irrelevant. You simply do not have /dev, /proc, /sys in your root
filesystem.

Reco

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Thread

Restore backup to KVM solitone <solitone@mail.com> - 2017-09-22 06:50 +0200
  Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-22 08:10 +0200
    Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-22 21:20 +0200
      Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-22 21:40 +0200
        Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-24 11:00 +0200
          Re: Restore backup to KVM <tomas@tuxteam.de> - 2017-09-24 11:20 +0200
          Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-24 12:00 +0200
            Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-25 21:10 +0200
              Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-26 08:50 +0200
            Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-25 21:20 +0200
              Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-26 08:50 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-26 13:10 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-26 13:20 +0200
                Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-26 17:40 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-26 21:20 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-26 21:50 +0200
                Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-27 09:00 +0200
                Re: Restore backup to KVM "Thomas Schmitt" <scdbackup@gmx.net> - 2017-09-27 09:50 +0200
                Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-27 10:40 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-27 14:10 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-27 19:00 +0200
                Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-28 09:00 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-29 06:40 +0200
                Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-29 08:40 +0200
                Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-30 13:10 +0200
                Re: Restore backup to KVM solitone <solitone@mail.com> - 2017-09-30 15:50 +0200
                Re: Restore backup to KVM Reco <recoverym4n@gmail.com> - 2017-09-30 17:00 +0200

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