[clue] Ack! (recovering busted disks - (fixed)

Tue Apr 26 14:31:56 MDT 2016

This was done on Fedora 23 with LVM for everything except /boot as well.
Dump runs on the VFS layer not the device layer, LVM is technically device
layer think of it like this:

file -> filesysystem -> lvm -> device

Dump operates at the filesystem layer, so getting a bad superblock means
that you likely actually have a bad superblock.  Try running fsck against
that filesystem and see what you get.

On Tue, Apr 26, 2016 at 8:19 PM, Charles Burton <charles.d.burton at gmail.com>
wrote:

> If you want you can also add compression:
>
> dump -0u -f - /home/mbean | gzip > /mnt/mbean.dump.gz
>
> On Tue, Apr 26, 2016 at 8:16 PM, Charles Burton <
> charles.d.burton at gmail.com> wrote:
>
>> I just verified that it works fine on LVM.  It should look like this:
>>
>> dump -0u -f /mnt/mbean.dump /home/mbean
>>
>> The /mnt/mbean.dump is the destination file to dump to.  The /home/mbean
>> is filesystem you wish to dump from.
>>
>> On Tue, Apr 26, 2016 at 8:10 PM, Mike Bean <beandaemon at gmail.com> wrote:
>>
>>> Sure looks that way.  Works on physical devices, didn't seem to care for
>>> my syntax.   It's dump -0u -f (destination) (source)?
>>>
>>>
>>>
>>> On Tue, Apr 26, 2016 at 2:08 PM, Charles Burton <
>>> charles.d.burton at gmail.com> wrote:
>>>
>>>> It doesn't work quite like you're thinking.  Dump doesn't care about
>>>> LVM, not at least as far as I know.  Try:
>>>>
>>>> dump -0u -f /mnt/mbean /home/mbean
>>>>
>>>> On Tue, Apr 26, 2016 at 8:04 PM, Mike Bean <beandaemon at gmail.com>
>>>> wrote:
>>>>
>>>>> Thanks for the tip.   At least at first blush it looks like I can't
>>>>> use dump and restore.   They only work on devices and not on logical
>>>>> volumes.  At least not on my logical volumes (I'm getting bad magic number
>>>>> in super-block.)   I think I'm going to play with it a  little while
>>>>> longer, see if I can figure out if it really can't handle or if I'm just
>>>>> PEBKAC.   Could also be this box.  I'm testing it on a box that I don't
>>>>> really care if it breaks
>>>>>
>>>>> dump -0u -f /mnt/mbean /dev/mapper/rootvg-homelv
>>>>>   DUMP: Date of this level 0 dump: Tue Apr 26 14:00:16 2016
>>>>>   DUMP: Dumping /dev/mapper/rootvg-homelv (/home) to /mnt/mbean
>>>>> /dev/mapper/rootvg-homelv: Bad magic number in super-block while
>>>>> opening filesystem
>>>>>   DUMP: The ENTIRE dump is aborted.
>>>>>
>>>>> Mike B
>>>>>
>>>>> On Mon, Apr 25, 2016 at 12:34 PM, Chris Fedde <chris at fedde.us> wrote:
>>>>>
>>>>>> I say this every time backups get mentioned but I have to say it
>>>>>> again.  I like dump.  Dump and restore are a perfect set of tools that
>>>>>> solve the backup problem neatly and flexibly.  And so far have not let me
>>>>>> down for either fat finger recovery or for full disk recovery.
>>>>>>
>>>>>> I find it silly that this tool that is integrated with the OS and
>>>>>> woks so well is overlooked by everyone. Even by the certification folks.
>>>>>>
>>>>>> Let me say it again.  I like dump. Maybe I need to write up a blog
>>>>>> article or something.
>>>>>> On Apr 19, 2016 6:33 PM, "Mike Bean" <beandaemon at gmail.com> wrote:
>>>>>>
>>>>>>> Yeah, I know ; )
>>>>>>>
>>>>>>> Mike B
>>>>>>>
>>>>>>> On Tue, Apr 19, 2016 at 3:49 PM, David L. Anselmi <
>>>>>>> anselmi at anselmi.us> wrote:
>>>>>>>
>>>>>>>> Mike Bean wrote:
>>>>>>>> > Theorhetically yes, and we did that, but as predicted, since I #1
>>>>>>>> noticed
>>>>>>>> > the box was down and #2 attempted to fix it, I therefore have
>>>>>>>> ownership of
>>>>>>>> > it now.   Have to look into a cheap scale able method to get
>>>>>>>> actual backups
>>>>>>>> > and stop depending on snap shots.   I suppose I could just back
>>>>>>>> it up.  But
>>>>>>>> > it's only a matter of time before someone notices the Jenkins box
>>>>>>>> has
>>>>>>>> > backups and complains that all the other boxes don't.
>>>>>>>>
>>>>>>>> You need to get a new job. Life's too short...
>>>>>>>>
>>>>>>>> And for everyone else, this is an example why you vote against
>>>>>>>> whatever the government wants to
>>>>>>>> spend money on.
>>>>>>>>
>>>>>>>> Dave
>>>>>>>> _______________________________________________
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>>>>>>>>
>>>>>>>
>>>>>>>
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>>>>>>
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>>>>>
>>>>>
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>>>>
>>>>
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>
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