Re: Random sd* devices numbering (udev)
On 09/03/2007 0:50, Bob McGowan wrote:
Hmm, I thought the LABEL/UUID mounting feature was part of udev??
No, AFAICT it's part of mount, see -L and -U options in man mount.
On the other hand, using udev, you may be able to figure out how to
write a naming rule that always names the devices correctly. I've no
experience with this and can only with you good luck if you choose this
route.
Indeed, in the /sys tree you can find various info related to devices,
which can help you uniquely identify them; I prefer this way rather then
relying on a label assigned by me, also because it works even for any
future partitions I might add on the same disks.
After reading some docs I wrote two satisfying udev naming rules,
although not what I meant to do initially:
SUBSYSTEM=="block", ATTRS{vendor}=="Areca", SYMLINK+="areca%n"
SUBSYSTEM=="block", ATTRS{vendor}=="Promise", SYMLINK+="promise%n"
Areca is the PCI-X SATA RAID controller, Promise is the external storage
unit; the software RAID devices on the builtin ICH7 SATA, where the
system is installed, are instead always automagically mounted fine, even
if their device sd* names sometimes change at boot, so I left this magic
alone.
I know these rules could fail if I add more devices from the same
vendors, but it's not planned at all :), and anyway could easily be
refined later.
So, the two devices are still named sda or sdb in a random way, but I
also have some symlinks which always identify them clearly: /dev/areca,
/dev/areca1, /dev/promise, /dev/promise1... And I can use these symlinks
in fstab and elsewhere.
Actually, I meant to completely change their naming, so my first test
rules were:
SUBSYSTEM=="block", ATTRS{vendor}=="Areca", NAME="sde%n", SYMLINK+="areca%n"
SUBSYSTEM=="block", ATTRS{vendor}=="Promise", NAME="sdf%n",
SYMLINK+="promise%n"
(just two lines, mind the word wrap)
But what happened was that the devices were assigned the sde/sdf names,
were assigned the areca/promise symlinks, but they were ALSO still
assigned the original random sda/sdb names. I couldn't find where this
assignment came from, I can't see any "sd" assignment in
/etc/udev/rules.d/*, so I removed my own names and settled down with my
symlinks to the default names.
I know there's a last_rule option which might have helped me prevent the
double names, but I didn't want to break anything by overriding system
naming rules.
Anyway, any info on why this happens is welcome.
--
Ciao,
Marco.
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