[CentOS] Re: Stuck at GRUB

Les Mikesell lesmikesell at gmail.com
Thu Nov 29 20:57:12 UTC 2007

Scott Silva wrote:

>> It won't hurt to re-install.  The tricky part is knowing where the 2nd 
>> drive in the set will appear when the first fails so you can do the 
>> configuration correctly.
> This isn't as tricky as you think. It just takes some thought.

Yes, but you need to think from the bios perspective, since you have to 
get the 'root (hdx,x)' value right for the grub invocation.

> PATA disks always will be where they are. They are set by their jumpers 
> for master/slave. But since most pata controllers lock when a drive 
> dies, it is less than optimal. You can get a little safer by either 
> using only the master part of the controller, or have each drives mate 
> on the opposite controller and opposite channel, IE pair primary master 
> with secondary slave and so on.
> Not for a production system, but will work OK for a home backup system.
> Sata usually will move to the next detected drive. IE... sdb will become 
> sda >IF< all drives are on the same controller. If the system has 
> multiple sata controllers, it could be a guess, or remove one and see 
> what happens.
> SCSI usually also moves to next drive because of the drives ID setting.

The situation I've normally seen is scsi and failure modes where the 
drive is not seen at all by the controller - but I don't know if that is 
always the case.  I don't think I've had an ide failure where I didn't 
have to disconnect the bad drive to boot anyway.

   Les Mikesell
    lesmikesell at gmail.com

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