From mboxrd@z Thu Jan  1 00:00:00 1970
From: "NeilBrown" <neilb@suse.de>
Subject: Re: Need urgent help in fixing raid5 array
Date: Wed, 7 Jan 2009 11:19:00 +1100 (EST)
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To: Mike Myers <mikesm559@yahoo.com>
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On Wed, January 7, 2009 10:54 am, Mike Myers wrote:

>
> With 15 hotswap drives in the system, I can tell you that device name
> changing is fraught with peril.  I am unfamilar with the /dev/disk/by-uuid
> functionality.  Is that documented in a howto somewhere?  How is that
> supposed to work?
>

/dev/disk/by-id is probably the one you want.
I don't know about documentation, but if you

 ls -l /dev/disk/by-id | grep -v part

and have a look it should make sense.
I get:
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 ata-ST3160812AS_4LS5YYHQ ->
../../sda
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 ata-ST3160812AS_4LS5YZDG ->
../../sdf
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 ata-ST3160812AS_4LS5YZJQ ->
../../sdc
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 ata-ST3160812AS_4LS5Z05D ->
../../sdd
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 ata-ST3160812AS_4LS5Z0B6 ->
../../sde
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 ata-ST3160812AS_4LS5Z0BH ->
../../sdb
lrwxrwxrwx 1 root root 11 2009-01-07 11:10
md-uuid-8fd0af3f:4fbb94ea:12cc2127:f9855db5 -> ../../md_d6
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 scsi-SATA_ST3160812AS_4LS5YYHQ
-> ../../sda
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 scsi-SATA_ST3160812AS_4LS5YZDG
-> ../../sdf
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 scsi-SATA_ST3160812AS_4LS5YZJQ
-> ../../sdc
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 scsi-SATA_ST3160812AS_4LS5Z05D
-> ../../sdd
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 scsi-SATA_ST3160812AS_4LS5Z0B6
-> ../../sde
lrwxrwxrwx 1 root root  9 2009-01-07 11:10 scsi-SATA_ST3160812AS_4LS5Z0BH
-> ../../sdb


which shows you my 6 drives (each listed twice) with their model numbers
and serial numbers.
If I move the drive around, they will get different 'sda' names, but
if you look at the lines in disk/by-id you can be sure that a given name
will always refer to the same physical device.
This is all managed by 'udev'.

NeilBrown