eric@lucii.org on Fri, 31 Jan 2003 13:49:07 -0500


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Re: [PLUG] device IDs on boot


Wayne:

Your guess on the drives is substantually correct.  It works like this:

hda  IDE bus 0 - Primary device
hdb  IDE bus 0 - Secondary device
hdc  IDE bus 1 - Primary device
hdd  IDE bus 1 - Secondary device

If there is IDE raid or other IDE controllers available then it's
hde, hdf, hdg,... etc [ no, etc is not a device :-)]

The  SCSI devices in my server are:

sda
sdb

 - instead of sc.  I'm not sure what the order is.  I suspect it relates
to the drive's position on the SCSI chain.   I'm sure there are
others that have more detailed info about the SCSI and RAID issues...
That's out of my scope :-D


Good luck.

Eric

On Fri, Jan 31, 2003 at 11:54:48AM -0800, Wayne Dawson wrote:
> I've sometimes wondered how the ids for physical disks are determined in 
> Linux.  Now I'm prompted again to wonder, and in this case it makes a 
> difference in what I'm doing.  While installing Linux, how do I know which 
> device id corresponds to any given physical device?  Choices for a 
> particular install I'm doing are:  hda (I think that's the IDE drive, which 
> I don't want to install on), sca (a SCSI device I assume), or scb (another 
> SCSI device I assume).
> 
> If anyone has a quick explanation of how this works or where I can find it, 
> please let me know.
> 
> Thanks,
> Wayne Dawson
> 
> More details for those who are interested:
> I'm trying to install Red Hat to be booted from a RAID.  I'm very new to 
> using RAID.
> 
> The RAID is in a separate chassis from the computer I'm using to install 
> the OS.  It has a hardware RAID controller (Intel SRCU31LA), and there are 
> several hard disks in the RAID chassis.  The computer also has an IDE disk, 
> but ultimately this computer will not be used with this RAID (we haven't 
> bought the new computer yet).
> 
> In the (text based) Red Hat install program, I was given the following 
> options to install onto:  hda, sca, and scb.  Not knowing how these device 
> names are determined, I guessed sca was where I wanted to install.  The 
> install completed and now I have a system that will not boot without the 
> boot floppy (a RAID controller vs OS compatibility issue I suspect), but it 
> does indeed require the SCSI chassis to be powered on so apparently the 
> bulk of the OS resides there.  However, I'm confused about this because my 
> RAID controller claims my RAID HOST has a status of "fail" (It's RAID level 
> 5 by the way, with 3 disks).
> 
> Perhaps the disk that is not configured as part of a RAID is available 
> through the RAID controller as a standalone disk, and that's what I 
> installed the OS on?
> 
> _________________________________________________________________________
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> 

-- 
------------------------------------------------------------------------
#   Eric Lucas 
========================================================================
I count him braver who overcomes his desires than him who conquers his
enemies; for the hardest victory is over self. 
  --Aristotle
_________________________________________________________________________
Philadelphia Linux Users Group        --       http://www.phillylinux.org
Announcements - http://lists.netisland.net/mailman/listinfo/plug-announce
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