[GTALUG] Hints for upgrading

[Lennart Sorensen]

On Wed, Jul 27, 2016 at 01:55:13AM -0400, William Park via talk wrote:
> I just upgraded from Slackware-14.1 to 14.2.  That's almost 3 years in
> between. :-)  Here are what I did or have...
> 
> 1. Single root filesystem /dev/sda1.  For boot drive, you need MBR, but
> you can lump everything into one partition.  When upgrading,
>     - before "install", move all the old directories into /.old
>     - during "install", don't partition or format /dev/sda (obviously)
>     - after "install", copy files from /.old/etc to /etc, file by file
>       but only when necessary (more later).
> 
> 2. For non-boot harddisks, use the entire harddisk without partition,
> like /dev/sdb instead of /dev/sdb1.  Yes, you can format EXT4 or BTRFS
> on the whole disk.
> 
> 3. You can't just copy blindly from /.old/etc to /etc, because
> formats may be different, new options may be introduced, etc.
> 
>     - obviously, if files are the same, don't copy.
> 	cd /.old/etc
> 	find . -type f | while read f; do diff -q $f /etc/$f && echo $f; done
> 	find . -type f | while read f; do diff -q $f /etc/$f && rm $f; done
> 
>     - after that, diff and merge into /etc manually, file by file,
> 	vimdiff X /etc/X
> 
> 4. If you plan to move the harddisk to another machine (like I do), then
> use MBR.  Problem with EFI is that it writes the boot entry in BIOS.
> Well, on a new motherboard, boot entry is not there, so you can't boot.
> You have to dig into EFI shell, and manually select your .efi.\

That would mean not supporting drives over 2TB.  Not working if the
machine only boots EFI (some exist, and some are configured that way).

It should be possible to make a copy of the grub .efi file using the
default name which should get booted automatically on most machines.

On some machines you would need a startup.nsh file instead.  For example:
# cat /boot/efi/startup.nsh
fs0:\EFI\debian\grubx64.efi

I have that on a virtualbox install running in UEFI mode because
virtualbox's UEFI implementation is toptally @#$@#$ stupid and doesn't
actually store the non volatile EFIVARS.

-- 
Len Sorensen