[Eclug] Debian no longer recognized partitions

  • Previous message: [Eclug] Debian no longer recognized partitions
  • Next message: [Eclug] Debian no longer recognized partitions
  • rohit the great ro at rohitnet.dyndns.org
    Sat Nov 18 11:13:59 EST 2006

     

    Great news!  Just curious, when you type fdisk -l /dev/sda, does sda1 
    appear as type 83 or type fd?
    
    Rohit
    
    Chacko Cherackal wrote:
    > Ok, its reassuring to know I can follow up on these steps without 
    > risking permanent damage.  I was prepared to spend my morning fiddling 
    > with mknod, but as I was searching online for the correct major and 
    > minor device codes I came across a post that suggested using hdparm -z 
    > to force the kernel to reread the partitions.  I ran it on each device 
    > and it located the partitions perfectly.  A quick rebuild of the array 
    > and I'm back in business.  Thanks again for all the advice Jason and 
    > Rohit.
    >
    >> From: Jason Gurtz <jason at jasongurtz.com>
    >> Reply-To: "Eastern Connecticut Linux Users' Group" 
    >> <eclug at lists.eclug.net>
    >> To: "Eastern Connecticut Linux Users' Group" <eclug at lists.eclug.net>
    >> Subject: Re: [Eclug] Debian no longer recognized partitions
    >> Date: Fri, 17 Nov 2006 13:23:29 -0500
    >>
    >> On 11/17/2006 11:04, Chacko Cherackal wrote:
    >> > If this doesn't work I'm going to try Jason's suggestion of forcing
    >> > recognition using mknod.  I'm holding off to use that as a last resort
    >> > because it seems like something I could use to muck things up even 
    >> further.
    >>
    >> Terminology is a bit off here...  All mknod does is create files[1]
    >> there is no "recognizing" or anything like that going on.  UDEV and
    >> similar are the ones that do auto-recognition.  As you're finding out,
    >> this type of modern functionality is not very long in the tooth.  This
    >> manual device creation also used to be handled by a script (even an
    >> executable in some cases) called MAKEDEV.  I believe that MAKEDEV was a
    >> redhat invention, eons ago.  One problem (besides extreme pain in
    >> dealing with dynamic hotpluggable hardware) with manual device node
    >> creation is that the /dev directory was typically cluttered with
    >> hundreds of nodes that pointed to hardware that didn't even exist in the
    >> system.  The worst offender was probably the dozens and dozens of serial
    >> ports, left from the days of many serial terminals operating off of one
    >> server.  With dynamic detection and creation, what you see is what you
    >> have, unless it doesn't work, which leads to your situation.[2]
    >>
    >> If you make a mistake using mknod, you won't have screwed anything up,
    >> and can just delete the files you have created.  I think, but am not
    >> sure, that you may be able to create these device files not just in
    >> /dev, but anywhere you want "just in case" (e.g. create /root/dev/sda1
    >> etc...)  Then it's just a matter of using your software raid tools to
    >> tie together those device files that you created
    >>
    >> ~Jason
    >>
    >> -- 
    >> [1]  OK OK they're device pointers and not *really* files in the sense
    >> that they contain data.  They are however, just files as far as the
    >> filesystem is concerned (e.g. you can ls/rm/cat/echo "foo" > to/from
    >> them just like any other file). NOTE: doing some of those things NOT
    >> necessarily recommended!
    >>
    >> [2] Trivia: Windows has had this dynamic device creation and
    >> coresponding device nodes for quite some time.  If you dig into the
    >> kernel API, you can find such things as \Device\Harddisk1 and so on.  If
    >> you look at OpenVMS (red-headed stepfather to NT), you will see these
    >> same names...  As is so painfully typical under windows, the user can
    >> not directly interact with these special files, as one can under Linux.
    >
    > _________________________________________________________________
    > Get free, personalized commercial-free online radio with MSN Radio 
    > powered by Pandora http://radio.msn.com/?icid=T002MSN03A07001
    >
    
    
    

     

     

    More information about the ECLUG mailing list