Re: mapping usb disks to devices

2017-08-17 Thread Tzafrir Cohen 
On Wed, Aug 16, 2017 at 10:21:59PM +0300, Gabor Szabo wrote:
> Hi,
> 
> I have a USB hub connected to my Raspberry Pi and I have several
> external Hard disks connected to the USB hub.
> It seems the order the hard disks are mapped to the device files
> /dev/sda1 /dev/sdb1 /dev/sdc1 is random. On every boot it might be different.
> 
> This of course breaks the mapping I have in /etc/fstab for the mounts.
> 
> How can I solve this so I won't need to update /etc/fstab after every boot?

Standard udev rules create on my system the following 4 subdirectories
under /dev/disk:

  by-id  by-label  by-partuuid  by-path  by-uuid

Each directory has symlinks to either a disk or a partition. One of
those should describe your external disk properly.

If this is not good enough, you can make your own.

$ cat /etc/udev/rules.d/90-backup-usb.rules
ACTION=="add", ENV{ID_FS_LABEL}=="backup-boole-*", \
SYMLINK+="backup"

And in fstab:

/dev/backup /mnt/backup ext4rw,noauto   0   0


There are several backup disks with different labels. The backup disk
that is connected is mounted by the backup script, but /dev/backup is
created by the udev rule.

-- 
Tzafrir Cohen | tzaf...@jabber.org | VIM is
http://tzafrir.org.il || a Mutt's
tzaf...@cohens.org.il ||  best
tzaf...@debian.org|| friend

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Re: mapping usb disks to devices

2017-08-16 Thread Gabor Szabo 
Excellent. Thank you!
Gabor

On Wed, Aug 16, 2017 at 10:23 PM, Shay Gover  wrote:
> Use blkid.
>
> On Wed, Aug 16, 2017 at 10:21 PM, Gabor Szabo  wrote:
>>
>> Hi,
>>
>> I have a USB hub connected to my Raspberry Pi and I have several
>> external Hard disks connected to the USB hub.
>> It seems the order the hard disks are mapped to the device files
>> /dev/sda1 /dev/sdb1 /dev/sdc1 is random. On every boot it might be
>> different.
>>
>> This of course breaks the mapping I have in /etc/fstab for the mounts.
>>
>> How can I solve this so I won't need to update /etc/fstab after every
>> boot?
>>
>> Is there a way to map specific hard disks to specific device files?
>>
>> regards
>>Gabor

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Re: mapping usb disks to devices

2017-08-16 Thread Shay Gover 
Use blkid.

On Wed, Aug 16, 2017 at 10:21 PM, Gabor Szabo  wrote:

> Hi,
>
> I have a USB hub connected to my Raspberry Pi and I have several
> external Hard disks connected to the USB hub.
> It seems the order the hard disks are mapped to the device files
> /dev/sda1 /dev/sdb1 /dev/sdc1 is random. On every boot it might be
> different.
>
> This of course breaks the mapping I have in /etc/fstab for the mounts.
>
> How can I solve this so I won't need to update /etc/fstab after every boot?
>
> Is there a way to map specific hard disks to specific device files?
>
> regards
>Gabor
>
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> Linux-il mailing list
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>
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