[Discuss] Disk numbering

[gaf at blu.org (Jerry Feldman)]

On 10/01/2011 10:49 AM, Matt Iavarone wrote:
> On 10/01/2011 10:26 AM, Jerry Feldman wrote:
>> 2 weeks ago when I added a new 1.5TB ($49) HD to use as backup, my
>> drives were numbered sda, sdd, sde, and sdf. This prompted me to rewrite
>> my weekly disk health script to discover what drives are on my system.
>> All well and good. My /etc/fstab uses only UUID as does my RAID1. I shut
>> my system down last week when I went out of town for a couple of days,
>> and I found that the drives were renumbered again. I don't recall the
>> exact numbering, since I don't have anything that uses the drive numbers
>> other than my health script.  When I returned, I noticed an I/O error on
>> the new drive so I spent hours running fsck to bypass the bad blocks and
>> fix any errors. I'm watching closely to see over the next few days in
>> case I need to return the drive. After the fsck was completed, and the
>> drive tested good, I rebooted, and this morning I noticed another
>> renumbering (sda, sdb, sdc, sdd). The backup drive that was repaired is
>> still /dev/sdc. Now sda and sdb are the RAID1 pair.
>>
>> I guess I am just ranting because I know the kernel assigns the drive
>> numbers at boot time and I don't need to know anything about the drive
>> numbers unless I need to run something manually.
>>
>
> If you have dependencies on the disk lettering, then you can use udev
> rules to force them.
>
>
>
True, but the best way is not to depend on disk numbering at all,
especially when you have removable drives like I do. In my case above it
was just a bit comical that they got renumbered several times in the
last couple of weeks.

-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
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