Newbie scsi question

Hans-Werner Hilse hilse at
Thu May 4 06:12:43 PDT 2006


veeeeery off-topic (Linux specific), but...

On Wed, 3 May 2006 16:09:42 +0530 "Karthik Subramanian"
<karthik301176 at xxxxxxxxx> wrote:

> On linux, the disks from the JBOD are recognised as /dev/sd[a-n]. The
> hitch is that the device naming is not consistent across reboots; the
> first time around, /dev/sdb could refer to the first disk on the JBOD.
> The second time around, you don't know what it points to, as the
> assignment of device names to disks depends on the order in which the
> disks are recognised at boot time. Of course, there are fixes to this
> problem - like devlabel/udev, but they are essentially fixes to a
> problem that should never have been there in the first place.

udev is not a fix to this, it is the cause. You actually can use udev
to get stable device nodes. Most distros don't care, though. The linux
kernel provides a stable addressing in sysfs. udev should be configured
to use this and not just enumerate serially. So the problem isn't there
"in the first place". Device node creation is already a userland task
in linux and I can't see nothing wrong with that.

This will probably be a design question for dfbsd as well for the devfs
reimplementation: What gets done in the kernel and what's left for
userland when it gets to device naming?


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