Newbie scsi question

Chuck Tuffli ctuffli at
Wed May 3 06:31:20 PDT 2006

On 5/3/06, Karthik Subramanian <karthik301176 at xxxxxxxxx> wrote:
. ..
Here's the problem:
Consider a typical SAN setup - an FC switch with a couple of JBOD's
and a couple of machines hooked up to the switch.
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.
. ..
In this kind of a situation, what does DragonFly do to ensure that the
disk names are consistent across reboots?
Unfortunately, DragonFly (and most of the other *BSDs I think) doesn't
have a good answer for persistent binding. You can setup the kernel to
"wire down" a particular bus/target/lun to a specific device, but I
don't think this would work for SANs.

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