Mounting UFS partition by lable using dsbmd

S

sprock

Hello,

I have a portable USB drive that I would like to use for backup. I have on it a UFS partition labeled "Backup". I have been using dsbmd to mount removable media. By default it mounts them as /media/da0p1 etc, i.e using the geom/partition names. I want to mount my portable drive by label as /media/Backup so that I can move it between multiple machines and have a consistent mount point. I looked through dsbmd but found no info on how to do this for as UFS filesystem. Can it be done? If so could someone share an example?

Thanks,
sprock
 
I am not familiar with dsbmd. After the tunefs command you should see the label with glabel list, like here on my da0p4 in the code below. glabel(8) can only change glabel labels but it can show various other types, including UFS labels. It shows up at the entry 1. Name: ufs/Backup; that is the name that is being provided to the OS. The sequence below starts with the partition unmounted. When unmounted, you' ll be able to see both entries /dev/ufs/Backup and /dev/da0p4. When you mount the partition as /dev/da0p4 the UFS label is being hidden by the OS: see command [7]. This is called GEOM withering. When you unmount, the label appears again at /dev/ufs/ (see command [9]). Mounting it by the UFS label entry /dev/ufs/Backup gives the desired result. Adapt your values for fstab accordingly.
Code: 
[1] # glabel list da0p4
Geom name: da0p4
Providers:
1. Name: ufs/Backup
   Mediasize: 69206016 (66M)
   Sectorsize: 512
   Stripesize: 0
   Stripeoffset: 202395648
   Mode: r0w0e0
   secoffset: 0
   offset: 0
   seclength: 135168
   length: 69206016
   index: 0
Consumers:
1. Name: da0p4
   Mediasize: 69206016 (66M)
   Sectorsize: 512
   Stripesize: 0
   Stripeoffset: 202395648
   Mode: r0w0e0

[2] # ls /dev/da0*
/dev/da0    /dev/da0p1    /dev/da0p2    /dev/da0p3    /dev/da0p4
[3] # ls /dev/ufs/
Backup
[4] # mount -w -t ufs /dev/da0p4 /tmp
[5] # mount | grep /tmp
/dev/da0p4 on /tmp (ufs, local)
[6] # ls /dev/da0*
/dev/da0    /dev/da0p1    /dev/da0p2    /dev/da0p3    /dev/da0p4
[7] # ls /dev/ufs/
ls: /dev/ufs/: No such file or directory
[8] # umount /tmp
[9] # ls /dev/ufs/
Backup
[10] # mount -w -t ufs /dev/ufs/Backup /tmp
[11] # mount | grep /tmp
/dev/ufs/Backup on /tmp (ufs, local)
[12] # ls /dev/ufs/
Backup

I don't know if you have a specific reason to want to use UFS labels but, you might also consider using GPT labels. Those are universal and not tied to any particular filesystem (or even OS); the only prerequisite is that you create the partition as a GPT partition of course.
 
Hello,

Thanks for the response.

I don't want the have an entry for this removeable device in /etc/fstab. I was hoping that dsbmd would be capable of using the label to create a mountpoint and mount the disk. Having labeled the partition using gpart modify I can see the entry in /dev/gpt but dsbmd ignores it. Indeed, based on my experiments dsbmd seems not to read its own config file.

Oh well.

Thanks agian,
sprock
 
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