Re: Adding a new boot disk while keeping old disk

[Charlie Gibbs <cgibbs@surfnaked.ca>]

Some of you may recall my account of trying to install a new disk (in
my case a 1TB NVMe stick) for use as a boot device.  There has been
another thread or two from other people dealing with the same issue,
so it seems to be a hot topic.

I'm still unwilling to give up all my installed packages and
customizations and rebuild the system from scratch, when all I want
to do is copy existing directories to a new boot drive.  My own data
files all live in /home, a separate partition - no problem there.
But many binaries have been installed in places like /usr/bin; their
configuration files may or may not be in /home, but I'd rather not
lose them wherever they are.

Here's the process I've been trying so far:

1. Do a network install on the new drive; to be really belt-and-
suspenders, make sure everything is completely updated:
    sudo apt update
    sudo apt upgrade

2. Re-boot from the original drive and update everything:
    sudo apt update
    sudo apt upgrade
At this point the old and new systems' root partitions should be
as alike as possible, aside from my own customizations.

3. Mount the new drive's root partition somewhere that I can access
from the original drive:
    sudo mount /dev/nvme0n1p2 /mnt/backup

4. Save the new system's /etc/fstab:
    sudo cp -p /mnt/backup/etc/fstab ~

5. Copy directories from the original drive to the new drive:
    sudo rsync -av /bin   /mnt/backup
    sudo rsync -av /etc   /mnt/backup
    sudo rsync -av /lib   /mnt/backup
    sudo rsync -av /lib64 /mnt/backup
    sudo rsync -av /opt   /mnt/backup
    sudo rsync -av /sbin  /mnt/backup
    sudo rsync -av /usr   /mnt/backup
    sudo rsync -av /var   /mnt/backup
    sudo rsync -av /home  /mnt/backup

6. Restore the new drive's /etc/fstab:
    sudo cp -p ~/etc/fstab /mnt/backup/etc

7. Re-boot from the new drive and cross your fingers.

The system comes up with an xfce login window, but I can't log in
using my regular user ID.  Sometimes the screen just goes black,
then after a couple of seconds re-displays a blank login screen.
Lately, though, I've been getting a window with the message:
    Xsession: warning: unable to write to /tmp;
    X session may exit with an error.
Clicking on "okay" makes the screen goes black; after a
couple of seconds it then returns to an empty login screen.
However, I can log in as root, which suggests some sort
of permissions issue, but it doesn't seem to be with /tmp:

drwxrwxrwt  12 root root  4096 Dec  9 11:58 tmp

To further muddy the waters, I can SSH in from another machine
using my regular user ID.

I'd like to resolve this, but if not I can always fall back to the
original drive.  Anybody wanna buy a lightly used 1TB NVMe SSD?

--
/~\  Charlie Gibbs                  |  "Some of you may die,
\ /  <cgibbs@kltpzyxm.invalid>      |  but it's a sacrifice
 X   I'm really at ac.dekanfrus     |  I'm willing to make."
/ \  if you read it the right way.  |    -- Lord Farquaad (Shrek)