An opportunity to investigate the fstab thing?

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kmathern
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Re: An opportunity to investigate the fstab thing?

#51 Postby kmathern » Fri Dec 02, 2011 6:03 pm

joany wrote:I mount a shared folder in order to transfer files between the host and the guest. The host folder isn't visible from the guest until it's mounted in the guest. Of course I could mount it manually, but it's more convenient to mount it via fstab at boot time.


I found this in the virtualbox.org tutorials. (it's dated 27 Mar 2009, so it may or may not still apply)

It recommends putting the mount command in the /etc/rc.local init script instead of mounting the shared folder with fstab.
https://forums.virtualbox.org/viewtopic.php?t=15868 {4th paragraph}

.... If you want to have it mount automatically upon each boot, put the mount command in /etc/rc.local (Debian based distro's), or whatever script is run at the end of the boot process. The Shared Folders service should mount them automatically, but that doesn't always happen.
Using /etc/fstab has little effect, because that file is processed before the SF module is loaded and will fail to mount the share. Sometimes, the share does get mounted because the GA check for it when they are loaded upon boot, but it's very flaky, meaning it doesn't work most of the time. You're better of with the first option. ....

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Re: An opportunity to investigate the fstab thing?

#52 Postby joany » Fri Dec 02, 2011 6:06 pm

lucky9 wrote:As I said, I've never had to mount the shared folder when using VB. I always assumed it was available for use and when needed it was. I guess it's done automatically (during setup) so when I need to transfer files I can.

These instructions cover Guest Additions and shared folders: http://www.virtualbox.org/manual/ch04.h ... redfolders

Early versions of VirtualBox required mounting shared folders manually at run time or through /etc/fstab:

In a Linux guest, use the following command:

mount -t vboxsf [-o OPTIONS] sharename mountpoint

To mount a shared folder during boot, add the following entry to /etc/fstab:

sharename mountpoint vboxsf defaults 0 0


However, I see that beginning with V4.0, mounting is done automatically by Guest Additions.

Starting with version 4.0, VirtualBox can mount shared folders automatically, at your option. If automatic mounting is enabled for a specific shared folder, the Guest Additions will automatically mount that folder as soon as a user logs into the guest OS. The details depend on the guest OS type:


I've been using manual mounting since I began using VirtualBox, back in Version 2.x. Call it force of habit. I'm not here to defend using the manual method. The only reason I'm bringing this up in this thread is because it's a convenient way to test out the fstab bug. I'm confident the bug will appear regularly in a SM 11.0 guest with the modification, so the bug can be repeated and tested on a standard (virtual) hardware platform.

If you don't want to test the bug using my method, you don't have to. The choice is yours
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Re: An opportunity to investigate the fstab thing?

#53 Postby Danum » Fri Dec 02, 2011 6:20 pm

I'm confident the bug will appear regularly in a SM 11.0 guest with the modification, so the bug can be repeated and tested on a standard (virtual) hardware platform.

First it is not a VurtualBox bug, VurtualBox is made to install in Debian, which because of all the problems with fstab updated along with other main stream Linux distro's to grub2,
VBox installs with no problems in any of the debian current releases as they all use Grub2..
Also of note Debian stable is very conservative in there choice of software and do not advise users to install Grub2 just for fun they do it for a reason
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Re: An opportunity to investigate the fstab thing?

#54 Postby lucky9 » Wed Dec 07, 2011 2:25 am

Well the fstab thing hit me today but with everything else that was going on I doubt that my data will be of help.
At one point I believed I had a bad external hard disk because Clonezilla wouldn't see all of the partitions on it. Difference partitions at different times of course.

I also had a mangled file system (Ext3) on my /home partition. It took most of the afternoon to get back to normal....mainly because of a bad Image which didn't work secondary to the file system being hashed.

Ended up having to reset the KDE and Group settings with the Mepis User Assistant. I believe that or correcting the file system enabled the System Assistant to install GRUB correctly. But I can't be sure as that was just the last thing that cleared up. I was beginning to wonder if anything would fix the ability to install GRUB. It may well have been both working together causing that problem.

During all of this my fstab was mangled. Nothing was above the dynamic line. Nothing. Repaired with the Mepis LiveDVD using KWrite. The System Assistant for GRUB. User Assistant for the Permissions, etc. and the good old Command Line for the file system and some other checking.

While things were not totally calm this afternoon and early evening....I haven't had this much fun in a long time. Thank you, Warren.
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Re: An opportunity to investigate the fstab thing?

#55 Postby Utopia » Wed Dec 07, 2011 4:41 am

Well the fstab thing hit me today

Did you find anything in the log files that could give a clue?
If you could repeat the whole mess with boot logging enabled, you could have another day of fun. And get some valuable information for Warren.
Seems like you have to go pretty far to be sure of destroying the fstab. That must be the reason why I haven't been able to do it. My small experiments haven't been close to the complete mayhem you created. Good idea, even if it wasn't intentional.
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Re: An opportunity to investigate the fstab thing?

#56 Postby Zevon » Wed Dec 07, 2011 5:39 am

Perhaps it's something in the air at around this time because on boot up yesterday evening my system wobbled again. I think the cause of it was because I had removed a USB keyboard dongle without letting the system unload it properly and then put it back before the system was started again.

At least the only error message that came up suggested that all was not well with it and though the machine booted through it wasn't happy - see fstab below. <grin>

# Dynamic entries below
/dev/sda1 /mnt/sda1 ext3 noauto,users,exec,relatime 0 0
/dev/sda2 swap swap sw,pri=1 0 0
/dev/sda3 /mnt/sda3 ext3 noauto,users,exec,relatime 0 0
/dev/cdrom1 /media/cdrom1 udf,iso9660 noauto,users,exec,ro 0 0
/dev/sr0 /media/cdrom1 udf,iso9660 noauto,users,exec,ro 0 0

I only have one optical drive and I could have sworn that it was designated /dev/cdrom not /dev/cdrom1 before this latest glitch.

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Re: An opportunity to investigate the fstab thing?

#57 Postby Utopia » Wed Dec 07, 2011 5:57 am

I had removed a USB keyboard dongle without letting the system unload it properly and then put it back before the system was started again.

That was a good experiment. One of the best yet. Shows clearly how the fstab error happens.
Can you repeat it?
Enable bootlog first to (hopefully) find more details.
Enable it in the file /etc/default/bootlogd
BOOTLOGD_ENABLE=Yes
The bootlog then shows up in /var/log/boot
Had to google for how to enable bootlog, had forgotten it completely.
Henry

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Re: An opportunity to investigate the fstab thing?

#58 Postby Utopia » Wed Dec 07, 2011 6:43 am

If you can find out how to reproduce the error with a USB keyboard, Warren gets a chance to fix it.
Henry

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Re: An opportunity to investigate the fstab thing?

#59 Postby Zevon » Wed Dec 07, 2011 7:03 am

Utopia wrote:
I had removed a USB keyboard dongle without letting the system unload it properly and then put it back before the system was started again.

That was a good experiment. One of the best yet. Shows clearly how the fstab error happens.
Can you repeat it?
I'll certainly try, as soon as I finish up some stuff I'm doing.
Utopia wrote:Enable bootlog first to (hopefully) find more details.
Enable it in the file /etc/default/bootlogd
BOOTLOGD_ENABLE=Yes
The bootlog then shows up in /var/log/boot
Had to google for how to enable bootlog, had forgotten it completely.
Henry


Heh heh, I had bootlog enabled from a while back but had forgotten about it. With any luck there will be something useful in there when/if I can reproduce the glitch.

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Re: An opportunity to investigate the fstab thing?

#60 Postby Utopia » Wed Dec 07, 2011 1:27 pm

Enabling bootlog was easier said than done. Mine is producing nice empty documents.
It's surprising how stable Mepis is when you try to crash it.
If I was a computer, I should have been seriously disturbed when someone connects and disconnects an USB-stick (with strange signs in the name) during the boot process.
Henry


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