Path: csiph.com!weretis.net!feeder6.news.weretis.net!feeder8.news.weretis.net!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod
From: "Rick Thomas" <rick.thomas@pobox.com>
Newsgroups: linux.debian.user
Subject: Re: Disks renamed after update to 'testing'...?
Date: Tue, 18 Aug 2020 10:40:02 +0200
Message-ID: <AF5jY-3XP-9@gated-at.bofh.it>
References: <AF5jY-3XP-11@gated-at.bofh.it> <AEX33-7kr-1@gated-at.bofh.it>
Old-Return-Path: <rick.thomas@pobox.com>
User-Agent: Cyrus-JMAP/3.3.0-191-gef79d59-fm-20200818.001-gef79d590
MIME-Version: 1.0
Content-Type: text/plain
Approved: robomod@news.nic.it
Lines: 38
Organization: linux.* mail to news gateway
Sender: robomod@news.nic.it
Xref: csiph.com linux.debian.user:226274

On Mon, Aug 17, 2020, at 4:42 PM, hobie of RMN wrote:
> Hi, All -
> 
> My brother has been issuing "mount /dev/sdb1" prior to backing up some
> files to a second hard disk.  He lately upgraded to 'testing', and it
> appears (from result of running df) that what the system now calls
> /dev/sdb1 is what he has thought of as /dev/sda1, the system '/'
> partition.
> 
> Thanks to the UUID= mechanism, his system still boots properly, but 'mount
> /dev/sdb1' is inappropriate now, could even be the path to madness. :)
> 
> Two questions, then: (1) What caused this shift of device naming? And (2)
> How do we fix it?  Is this something that can be changed in the BIOS? 
> But, if so, what caused it to change in the first place?
> 
> Thanks for your time and attenton.

The /dev/sdx names for devices have been unpredictable for quite a while.  Which one is sda and which sdb will depend on things like timing -- which one gets recognized by the kernel first.

The best solution is to either use UUID or LABEL when you fsck and/or mount the device.  So:

1) Use "df" to find out the device name that the kernel decided to use for your backup disk this time.  Let's assume it's /dev/sda1.

2) label that device with the "tune2fs" command (assuming your device contains an ext[234] filesystem.  If not, check the man pages for the filesystem you are using.)  e.g. "tune2fs -L BACKUP /dev/sda1".

3) then when you want to mount or fsck  the device (you do fsck it before mounting it, right?) use "LABEL=BACKUP" instead of "/dev/sdb1".
        fsck LABEL=BACKUP
        mount LABEL=BACKUP
4) If you're into typing long strings of random characters, you can instead skip the label step and do
        fsck UUID=..................
        mount UUID=..................
But that's only for masochists, IMHO.

In any case, read the man pages before you try anything, so you'll know what your doing.

Enjoy!
Rick