Re: totally random "VFS: Cannot open root device"

[Tejun Heo]

0602@xxxxx wrote:
> Hi!
>
> (Please CC me your answers as I am not subscribed.)
>
> I have a problem with 2.6.14.3 kernel (but this probably isn't too 
> version-specific). I have a kernel which succesfully boots on totally 
> random basis (cca 70% is success). My root partition resides on a SATA 
> disc connected to a controller on Intel 6300ESB ICH southbridge (mb 
> Intel se7320vp2). There is a reiserfs 3 filesystem on my root partition. 
> Without any changes to configuration (os or bios or whatever) I 
> sometimes get:
>
> VFS: Cannot open root device "801" or unknown block(8,1)
>
> Could this be some timeout issue, or indication of crappy hw? I've tried 
> this about 10 times (immediately ctrl+alt+del on successfull boot or 
> reset button on aforementioned panic) and I saw no regularities in this 
> misbehaviour.
>
> I sincerely appreciate any advice anyone can give.

[CC'ing linux-ide]

Hello, 0602.  :-)

Can you please post dmesg of a successful booting?  That will tell us 
which SATA controller/disks you are using.  Also, the boot log of a 
failed boot will be very helpful - the best way to get this is via 
serial console.  If you don't have access to serial console, taking note 
  / picture of the part where SATA detection fails will do too.

Also, when the machine boots successfully, does it work without 
generating disk related kernel logs?  Just perform any IO-heavy 
operations - cp'ing directories which contain large files, 
tar/untarring... - and see if the kernel complains about anyting.

--
tejun
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