fstab and device labels

shakeshuck

How do I use device labels in fstab?

I gave a disk a label of netbsd_root, thinking (from my inadequate understanding of the man pages) that I could then use NAME=netbsd_root/a in fstab to refer to the disk.
Needless to say it left my system unbootable and I had to resort to reading ed tutorials to get it back!

The dkctl man page says that's the right format, but to use fdisk or gpt to make it permanent?
In the wiki it also uses the term in a wedge-enabled system which I also don't know how that applies to fstab?

I'm a bit lost.

rvp

shakeshuck The NAME=something (you don't need the /a part) works if you have GPT partitions (aka. wedges) with labels. Not sure if that works with the FFS filesystem labels. My /etc/fstab is:

NAME=NetBSD_main	/		ffs	rw,log,noatime	1 1
NAME=NetBSD_swap	none		swap	sw,dp
kernfs			/kern		kernfs	rw
ptyfs			/dev/pts	ptyfs	rw
procfs			/proc		procfs	rw
tmpfs			/var/shm	tmpfs	rw,-m1777,-sram%50
tmpfs			/tmp		tmpfs	rw,-m1777,-sram%50

Here's mine (non-gpt) ffsv2

# NetBSD /etc/fstab

/dev/wd0a			/	ffs			rw,noatime,nodevmtime	 1 1
/dev/wd0b			none	swap			sw,dp			 0 0
tmpfs		/tmp		tmpfs	rw,-m=1777,-s=ram%25
kernfs		/kern		kernfs	rw
ptyfs		/dev/pts	ptyfs	rw
procfs		/proc		procfs	rw
tmpfs		/var/shm	tmpfs	rw,-m1777,-sram%25

shakeshuck

I think this is where the complications start!

After install, my fstab is more like pin's. No MBR or GPT that I'm aware of. The issue begins if I try to connect a disk array; even with only one disk added, for some reason it gets priority over the install disk so what was sd0x (the root disk) becomes sd1x and I can't boot without intervention. That's why I thought NAMEing the fstab was the way to go. But if I'm reading it right, I don't have a GPT partition?

I'll try it without the /a and see if that works.

shakeshuck

shakeshuck
Wait a minute, though - I'd changed the disklabel, and thought I was referring to that; that's why name/a & name/b for the slices? rvp has a different NAME for each mount point. I can't do that within disklabel?

rvp

shakeshuck I can't do that within disklabel?

I think that FOO/a etc., syntax is correct if the disklabel has a, er, label. So, if your disklabel (or, is it a diskpack?) has the label FOO, then you should be able to use FOO/a, FOO/b for NAME= provided the kernel creates wedges for BSD disklabels--which, unfortunately, is not enabled by default (options DKWEDGE_METHOD_BSDLABEL) in any of the x86 GENERIC kernels.

EDIT:
If I'm reading this right, you can use ROOT.a etc., and getfsspecname will substitute the correct root-device in place of ROOT.

shakeshuck

rvp

Thanks for this info rvp, I'll have a fiddle when I get chance...

dressupgeekout

I thought the NAME= thing ONLY works with wedges based partitions underneath a GPT.

rvp

dressupgeekout Same here, but, it looks like the kernel applies the label from an on-disk (ie. non-fictitious) disklabel on wedges created from BSD partitions. Haven't actually tried this out though... 😃