[mythtvnz] Storage drive won't mount

[Stephen Worthington]

On Tue, 23 Apr 2013 01:47:46 +1200, you wrote:

>On Mon, 22 Apr 2013 23:25:09 +1200, Stephen Worthington  
><stephen_agent at jsw.gen.nz> wrote:
>
>> On Mon, 22 Apr 2013 20:40:14 +1200, you wrote:
>>
>>>
>>> I had a power cut here about an hour ago and when the system rebooted I
>>> got a message: problem mounting /var/lib/mythtv
>>> I have /var/lib/mythtv on a 1TB drive.And the OS on a 160 GB drive.
>>> The drive is ok according to the disk utility.SMART data is good ran
>>> benchmark sucessfully.
>>> sudo mount /dev/sdb1 /var/lib/mythtv gives a wrong fs error.fstab looks
>>> fine.
>>>
>>> Any suggestions what to do?
>>> Or how to temporarily revert to /var/lib mythtv on sda1?
>>> I tried sudo umount /var/lib/mythtv but it tells me /var/lib/mythtv is  
>>> not
>>> mounted   -of course.
>>> Actually I think it has reverted by itself because it is recording to  
>>> some
>>> directory.
>>> Any ideas how to get my 1TB drive mounting again?
>>>
>>> Paul
>>
>> I have seen that error on JFS partitions when the partition was dirty
>> and needed the journal to be re-run against it after a crash.  It
>> should be fixed if you run:
>>
>>   fsck -C -f /dev/sdb1
>>
>> The -C just gets it to tell you what it is doing so you can see how
>> long you are going to have to wait.  The -f forces a full check of the
>> partition.
>>
>> Since I am paranoid about corrupted filesystems, whenever I have a
>> power failure or crash like yours, I always reboot into the repair
>> boot option - I forget what it is called exactly, but it is the next
>> line down in the Grub menu below the usual boot.  It boots in single
>> user mode, and provides a list of options for repairing things.  I
>> select the fsck one and let it run fsck on all partitions.  Then I
>> feel safe to reboot normally.
>>
>> _______________________________________________
>Thanks Stephen
>
>Yes it is JFS and the disk utility did state that it was not clean.
>As for  your second suggestion,my system does not usually show the grub  
>menu as it boots.
>I seem to recall that hitting the shift key or something during boot will  
>bring it up.

I always get the Grub menu on my systems, so I am not sure why you do
not.  I am sure there is an option to make it default to displaying
the menu.  Take a look at these:


http://askubuntu.com/questions/16042/how-to-get-to-the-grub-menu-at-boot-time-on-a-single-boot-system-not-dual-boot
  https://help.ubuntu.com/community/Grub2

>On another subject regarding booting, If the system boots with the TV  
>turned off the graphics
>card  doesn't get any information about the display type and consequently  
>I get no image
>on the screen.I usually wait and when there is no disk activity shown by  
>the drive LED,
>hit the reset button but I don't really like to have to do that.
>Is there another method (without being able to see a display) to get the  
>graphics to restart?
>I've tried to blindly step back to the shutdown option with <esc> and the  
>down arrow key,but
>that never works.
>I am assuming of course that the keyboard is functional at this point.

Hitting the reset button is a bad thing to do.  If you have to, it is
best to wait until activity stops and the hard disks have been quiet
for at least 10 seconds, so there is a chance they will have flushed
all the cached data to disk.  That usually works well with EXT3
partitions, but not so well with EXT4 which gets some of its improved
performance by not flushing things as EXT3 does.  JFS partitions will
normally be dirty on reboot after that (if they have been written to)
and will need at least their journal data re-written to their main
disk area, so always run fsck on them.

It would be possible to do a blind shutdown using one of the full
screen logins - I have had to do that on occasion when I have had
video driver problems and it does work.  Wait for all booting activity
to complete, Ctrl-Alt-F1, enter the username "root", then the root
password, then a "poweroff" or "reboot" command.  Make sure to leave a
delay for Ctrl-Alt-F1 to happen and again for the login to complete
before typing the command.  Practice it with the screen working to
make sure you know how it works.  Have you set a root password so you
can directly log in to do that?  Just do an "sudo passwd" command to
set the root password.

And if the PC is on a network, you should have ssh set up so that you
can do a remote login for this sort of thing.

It might also be possible to program a hotkey sequence somehow that
did a shutdown.  I have never tried doing hotkeys on Ubuntu, but I
think it is likely someone has done hotkey software for it.  Maybe
Win-S for shutdown.

As to getting the TV to work when it gets into that state, have you
tried unplugging it and plugging it in again at the PC?  Lots of video
cards will detect the plugging in and retry starting the video, so it
may just start working.  If not, then you should probably not be
relying on the EDID data from the TV to set the video mode.  There are
various ways of handling that, for example you can get a copy of the
EDID data and get the video drivers to work from that copy on hard
disk in Nvidia drivers.  Or you can put modelines in the xorg.conf
file to describe the modes required, and force the video drivers to
not look for EDID data.  These things get quite complicated though -
xorg.conf is a diabolical config file to work with.  What sort of
video card is it?

And what sort of TV?  Some TVs have updated firmware available to fix
problems like that.