Newbie scsi question

Justin C. Sherrill justin at shiningsilence.com
Wed May 3 06:29:02 PDT 2006


On Wed, May 3, 2006 6:39 am, Karthik Subramanian wrote:

> 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.

I've never had a fibre channel setup, so I can't confirm this, but at
least with IDE drives, I've thought the position of the disk determined
the device name - the first disk on the first controller is ad0, the
second is ad1, the first on the second controller is ad2, etc.  It could
be coincidence.






More information about the Users mailing list