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Re: Ubuntu error: invalid magic number, cannot boot (Mike Miller) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 4 Oct 2012 14:08:25 -0500 (CDT) > From: Mike Miller <mbmiller+l at gmail.com> > To: TCLUG List <tclug-list at mn-linux.org> > Subject: [tclug-list] Ubuntu error: invalid magic number, cannot boot > Message-ID: <alpine.DEB.2.00.1210031757310.25266 at taxa.psych.umn.edu> > Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII > > I installed Ubuntu 12.04 on a RAID1 array a few months ago and explained > it all here: > > http://permalink.gmane.org/gmane.user-groups.linux.tclug/20855 > > I have been running Unity on the box but I normally attach to it via VNC > (with IceWM) in an SSH tunnel. A few days ago the VNC session hung on me > and the Xvnc process was at 100% CPU. I had to kill it. (Probably a > known bug, but I'll skip that story for now.) Before starting it up > again, I ran update-manager from the console. I could see that there was > something seriously wrong with Unity -- the task bar on the side had only > one item in it, that was just a grayed out box, and it was unresponsive. > After running update-manager I rebooted. I don't know what the exit > status was for update-manager because it was gone and I don't know if it > did much. > > After rebooting, I have this error: > > error:invalid magic number > error:you need to load the kernel first > > Grub will show some options for other kernels. I have tried some, and > none of them will boot. They hang with a bunch of info on the screen. > > Any ideas on how to proceed? What tests should I be doing to find the > source of the problem? > > Thanks in advance. > > Mike > > > ------------------------------ > > Message: 2 > Date: Thu, 4 Oct 2012 23:11:47 -0500 (CDT) > From: Mike Miller <mbmiller+l at gmail.com> > To: TCLUG List <tclug-list at mn-linux.org> > Subject: Re: [tclug-list] Ubuntu error: invalid magic number, cannot > boot > Message-ID: <alpine.DEB.2.00.1210041953000.31634 at taxa.psych.umn.edu> > Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII > > Update -- It turns out that the oldest kernel on the list was able to work > in recovery mode which took me to a screen saying this: > > Recovery Menu (filesystem state: read-only) > > With options: resume, clean, dpkg, failsafeX, fsck, grub, network, root > and system-summary. > > Looking at system-summary it seems pretty normal to me. The RAID seems > intact. So I tried "resume" next. This got me back to the window > manager. > > Looking back, I'm wondering if my problem was that I didn't reboot the > system after one set of updates before installing another huge batch of > updates. This is from back when the system was starting to behave badly > but it was still running: > > Welcome to Ubuntu 12.04 LTS (GNU/Linux 3.2.0-26-generic x86_64) > 414 packages can be updated. > 116 updates are security updates. > *** System restart required *** > > It was asking for a reboot, but I didn't do it before updating the > packages. Clearly, I should have been keeping up on the updates -- I was > used to being reminded, but when I don't see the :0 display, I don't see > the update manager. Now when I ssh to the box I see this: > > Welcome to Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-23-generic x86_64) > 9 packages can be updated. > 5 updates are security updates. > > So I've dropped back a few kernel versions. What do you think I should be > doing at this point? I'm not sure what is wrong or how to fix it. Maybe > if I do the updates and reboot, I'll be back to where I want to be. > > Anyone? ;-) > > Mike > > > > On Thu, 4 Oct 2012, Mike Miller wrote: > >> I installed Ubuntu 12.04 on a RAID1 array a few months ago and explained >> it >> all here: >> >> http://permalink.gmane.org/gmane.user-groups.linux.tclug/20855 >> >> I have been running Unity on the box but I normally attach to it via VNC >> (with IceWM) in an SSH tunnel. A few days ago the VNC session hung on >> me and >> the Xvnc process was at 100% CPU. I had to kill it. (Probably a known >> bug, >> but I'll skip that story for now.) Before starting it up again, I ran >> update-manager from the console. I could see that there was something >> seriously wrong with Unity -- the task bar on the side had only one item >> in >> it, that was just a grayed out box, and it was unresponsive. After >> running >> update-manager I rebooted. I don't know what the exit status was for >> update-manager because it was gone and I don't know if it did much. >> >> After rebooting, I have this error: >> >> error:invalid magic number >> error:you need to load the kernel first >> >> Grub will show some options for other kernels. I have tried some, and >> none >> of them will boot. They hang with a bunch of info on the screen. >> >> Any ideas on how to proceed? What tests should I be doing to find the >> source >> of the problem? >> >> Thanks in advance. >> >> Mike >> > > > ------------------------------ > > _______________________________________________ > TCLUG Mailing List - Minneapolis/St. Paul, Minnesota > tclug-list at mn-linux.org > http://mailman.mn-linux.org/mailman/listinfo/tclug-list > > End of tclug-list Digest, Vol 94, Issue 1 > ***************************************** > The first thing I would try is booting into a shell and running fsck on your boot disk. Reboot the machine and press e in the grub screen for edit. Go to the kernel line and press e to edit that line. Then add to the kernel line init=/bin/bash when you boot you go straight to the shell. then do a file system check on your boot drive fsck -t ext3 /dev/sdax t is for file system type in this case ext3 and the x in sdax is your partition number. sda is for sata drives, if you have an ide drive use hdax Most of the time its a file system error and was very common when I was doing raid arrays in my advanced linux classes. Bad super block is also common. If you are still having troubles run fsck from a live cd/usb. But you will have to run the cd in live mode, mount the offending drive, and chroot into the drive. As a last resort you can update-grub from the live cd after you have chroot'ed into you installed environment. Let me know what you encounter. ,Ron