On 21/12/11 05:58 PM, Matthew R. Wilson wrote:

I am curious to know if there is an easy way to guess or identify the
device names of disks. Previously the /dev/dsk/c0t0d0s0 system made sense
to me... I had a SATA controller card with 8 ports, and they showed up
with the numbers 1-8 in the "t" position of the device name.

But I just built a new system with two LSI SAS HBAs in it, and my device
names are along the lines of:

I could not find any correlation between that identifier and the a)
controller the disk was plugged in to, or b) the port number on the
controller. The only way I could make a mapping of device name to
controller port was to add one drive at a time, reboot the system, and run
"format" to see which new disk name shows up.

I'm guessing there's a better way, but I can't find any obvious answer as
to how to determine which port on my LSI controller card will correspond
with which seemingly random device name. Can anyone offer any suggestions
on a way to predict the device naming, or at least get the system to list
the disks after I insert one without rebooting?

Hi Matthew,
By default the names for disks attached via mpt_sas(7d), or
mpt(7d) if your disks are new enough, is to use their WWN
as reported in the SCSI INQUIRY Page83 response.

The old paradigm you refer to is based on the physical id
of the device on a parallel SCSI bus. That doesn't scale
with SAS, and is something we're trying to move away from.

If you'd like some info about how we use devids and guids,
please refer to my presentation


For your particular configuration, if you note the serial
number and WWN of the device before you insert them, you
can match that up with info from  iostat -En  and/or prtconf -v.

James C. McPherson
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