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Re: Log files: location and description

On 10/07/2017 03:01 PM, David Wright wrote:
On Sat 07 Oct 2017 at 09:36:37 (-0500), Richard Owlett wrote:

I have a hypothesis, but I need to have facts to back it up.
1. During the installation process I need to inventory when and
   "as what" various USB devices are recognized. The installation
   target is a USB drive and Grub is being installed to its MBR.

It's all in /var/log/installer, specifically syslog.
partman has the partitioning, and hardware-summary gives
both that and related software summaries. That's all after
the event, of course. While the d-i is running, syslog
is under /var/log as normal.

My basic problem is not knowing what is "normal" ;)
This information should remedy my immediate problem.

2. Under particular circumstances it will fail to boot. I need
   to compare that log to that written when it successfully boots.

With expert install, the splash/menu screen goes away and boot
messages come out on the console in my experience.

The messages are clear enough as to what it sees as the problem. My intention was to explain why.

3. I need to know what happens during update-grub run from the HDD.
4. I need to repeat [2] but for the case that the the Grub menu is
   on the HDD.

update-grub runs grub-mkconfig which is a script, so I suppose
you could add set -x to make it print all its expanded commands
(as I do in .xsession).

I don't understand.
According to the man page neither update-grub nor grub-mkconfig have an "-x" option. The man page for xsession only mentions ".xsession" in passing. One reference refers reader to man page for xinit which I did not find informative.

Obviously I'm missing some background. What should I be reading?

Without getting into the specifics of that bug, ie UUID stuff,
it might be worth pointing out that it has been reported here that
a USB3 stick inserted at boot can demote the internal disk to
/dev/sdb. No idea if that's relevant here unless you're using
/dev/sdX without actually checking the by-id values that d-i
displays in the relevant places.

I was suspecting something similar but instead of vainly attempting to describe it on my own I wanted to quote log files. My USB3 device is a WiFi Hotspot. IIRC it can initially be recognized as a memory device before it initializes.

I wanted to establish that if the installer used UUIDs my symptom would disappear. I don't know if there would be unwanted side-effects.

As a side note I'm investigating a possible problem with os-prober. But I need information from logfiles to determine if there is an actual problem or just confused operator.