Last friday Mina Shokry joined in#Ubuntu+1 reporting an unbootable system after upgrading to Lucid. Even booting with rescue mode it was hanging without any error message, apparently it was after mounting the file systems (guessing by the "mounted filesystem" message).
After several hours trying all sort of boot options we are able to identify the problem.
The /proc/bus/usb on fstab which was previously required for USB support in VirtualBox mount was failing, however upstart/mountall (not sure where is the fault) did not provide an error and simply stopped the boot process.
The bug for the mount issue is bug 565109 .
I have also filed a bug for upstart, bug 565890, simply making it verbose when using rescue would allow to easily identify the problematic task.
If you use VB's USB support make sure you remove the /proc/bus/usb entry from your fstab.
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I've run into problems troubleshooting boot problems before due to Ubuntu's upstart setup.
ReplyDeleteThe source of the problem is two-fold. First the boot isn't verbose enough. It's already hidden by the splashscreen to start with, and if I disable the splash it's because I want to see what's going on underneath in as much detail as possible. To further hide things at this level isn't helping anyone.
Secondly, due to the boot tasks being launched in parallel, if the system freezes you don't have any sense of what caused it since it was running several tasks at that moment. If the boot process was sequential it would be a simple matter of identifying where it stopped.
Both of these problems make identifying boot problems more difficult than it should. I find myself booting other, more traditional, distros whenever I'm tracking down hardware problems. Of course if the problem is specific to Ubuntu I'm usually out of luck and can expect a long troubleshooting process ahead. Exactly what happened when you tried tracking down the VB USB problem.
I haven't tried Ubuntu server in the regard, but the desktop version is definitely not very admin friendly.
Hey, thanks for writing this post.
ReplyDeleteI had upgraded to Lucid on Beta2 launch but when I got stuck at this point, I just said "screw it" and went back to Karmic, promising myself I wouldn't upgrade until at least a month after final launch.
I'm usually able to work around the issues but couldn't find anything on this at the time and just had a bricked computer to show for it.
I definitely agree with Diogo in that debugging boot issues is very difficult. Recovery mode should twice as verbose and should execute things in a linear, single-threaded fashion. Plus things should be forced to announce what they're doing (so mountall should say which drive it's trying to mount before it mounts) so you can see what's borking the system.
I second the comments here. Linux is great
ReplyDeletewhen it works. When it breaks, there's not
enough information available (without significant digging) to fix it. I cut my teeth on Windows (not exactly a perfect OS either, but
when it breaks, there's generally more info available either as to why or as to what to do about it than there has been so far with Ubuntu.
I first entered Linux with Karmic Koala and am
now on Lucid Lynx Beta 2. Just had my system (after several upgrades) boot to a white Terminal window (after the "Try Ubuntu" option screen. I'm all for making improvements to Ubuntu - nothing extraordinary - upgrading (or changing) the File Explorer, upgrading software (VLC, Ubuntu Tweaks, Bleachbit - notably of late). There may very well be people who have no problems with said procedures. Invariably, one step two far, and I'm looking at a reinstall or downgrade.
Staying in place isn't always an option when the upgrade is "recommended" for better performance, stability, etc, but, all too often the end result is (for me) software / system incompatibilities which result in system crashes, behavior problems etc.
Linux seems to be a GREAT hobby OS if you REALLY like tinkering. I like Linux for what it does well, but, I'm growing tired of (and
getting pretty good at) reinstalling it when
things go horribly wrong.
I've asked for help when they do go wrong, but, it's never a simple process and I bear in
mind that often those I'm asking are doing so for free (with all that involves). Not complaining on that account, I just know that
free means that I take what I'm offered with a grain of salt. If it works and fixes the problem GREAT, if it doesn't, there's only so much ANYONE will do (or can or should be expected to do) for free.
Assuming any replies at all and assuming some significant degree of helpfulness.
I've reinstalled Linux more times in the few months I've been using it than I ever have over the years I've used Windows. Again, that doesn't (in my book) make Windows a better product by comparison, but, it's certainly not endearing me to Linux either.
I'd like to add that I do Tech Support for a living,
ReplyDeletehave for the last 8 - 10 years. From Win 3.1 up to
and including WinXP. I don't just use Google. I try to wring every useful bit of information I can out of it. Some of my searches look more like formulas:
linux ubuntu "lucid lynx" bleachbit deb -bz -gz (for example). I don't just ask questions as my FIRST resort. I try to find my own answers. I just happen to have the kind of problems that either have been answered a million times before with almost no two answers the same or "Just Me" type problems the kind that I can only hope someone with considerably more knowledge than I can provide (has the patience to) provide an answer for.
Sometimes I'm lucky and hit the nail on the head and
find a solution that fixes my problem.
I don't by any stretch think I'm alone in this.
Just didn't want anyone thinking I'm just looking for answers and not trying to learn or doing anything to help myself in the process.
I, like a LOT of other people, am learning a LOT,
but sometimes it would be nice just to be able to be productive without the "benefit" of the education.