Silly question

[Paul Gilligan]

I have not been on HP/UX for a couple of years, what is mean't by hardware path? and how can I decode it into device/lun...etc.

[A. Clay Stephenson]

Hi Paul:

The hardware path can include bus/bus translator/SCSI ID/LUN among others.

The decode varies a bit between platforms and devices but the easiest thing to do is an ioscan.

e.g. ioscan -fn will list all devices, the hardware paths, and the associated nodes.

Now here's the kicker.

/dev/dsk/c2t2d0 (controller 2, scsi ID 2, LUN 0) does not point to a unique hardware path even on the same machine. For example if you reload the OS c2 may become c1 because the 'c' number is really the instance number which means the order in which the card was discovered. This is especially true if you add a card to a machine and then reload the OS.

You might also be interested in the lsdev command which identifies major device numbers.

Man ioscan,lsdev for details.

Regards, Clay

[Victor_5]

H/W path is a numberical string of hardware components, notated sequentially from the bus address to the device address. Each number represents the location of a hardware component on the path to the device.

See "man ioscan" for more details.

[Bill Hassell]

The most important command is lssf to decode device files into what they really point to. Also, you can speed up ioscan with the -k option as in:

ioscan -kf

Or better yet:

ioscan -knfC disk

which shows all the disk channels and associated device files. You can find all LAN cards with:

ioscan -knfC lan

[Bill McNAMARA_1]

H/W path is specific to server class.
It is very important to understand when configuring SG and HA solutions, also in terms of performance you'd like to mirror across different busses to get perf benefit of the two and the ha considerations also.
HW addressing for SCSI is easier to understand than Fibre channel and Switching / disk array and most array manuals and server manuals describe it well there.
What you need to do is run ioscan -f
and try to match it to the physical layout of your server. that'd be the best learning experience for ioscan/hw other than a course.

PS: its not at all a silly question.

Later,
Bill

[Carlos Fernandez Riera]

I like silly questions...

All hardward path is based on the position on the box. Each type of box has differents hardware paths.

To see the beginig of hardware path , please go to the rear of box. Near of each slot for cards you will see a number like 0/8/12 or 2/0...


This is the hardware path for that card. All device generated for taht card ( disks... tapes..) will be preceded by this number when run ioscan.

[boley janowski]

As Carlos said you can look at the back and you will find some definition for each position, however use this as a way to confirm the ioscan information (sometimes these are located on the power supply and the power supply's get swapped out with the wrong information on them which can be disasterous if you were loading that box from a make recovery of another box and the lan cards dont match up properly).