topic Re: hardware paths in Operating System - HP-UX

hardware paths

geeta — Tue, 25 Oct 2005 18:49:58 GMT

hi,

I am fairly new to HPUX and fibre channels and raid systems, going through training in fact. If anyone could help with deciphering the h/w path frm an ioscan output..what the different numbers represent in the path and how does it differ for scsi and fibre? I am not sure if i am clear enough, so heres an example frm our training class: 8/0/2/0.8 ...by looking at this we are supposed to know this : c0t0d0 or something like that..really confusing and would appreciate if someone can explain it in simple terms so i understand how this works and how this helps troubleshooting whn we are looking at an ioscan output? thanx :)

Re: hardware paths

Granite — Tue, 25 Oct 2005 19:19:36 GMT

Hi Geetha,

Just look on this URL.,

http://docs.hp.com/en/32650-90854/ch12s09.html.

Rgds,Granite

Re: hardware paths

Granite — Tue, 25 Oct 2005 19:32:53 GMT

Hi,..

Is this working..

http://docs.hp.com/en/B2355-90053/ch01s04.html..

Re: hardware paths

geeta — Tue, 25 Oct 2005 19:46:37 GMT

The document is missing

Re: hardware paths

Denver Osborn — Tue, 25 Oct 2005 19:51:07 GMT

just a typo w/ the url... this should do it.

http://docs.hp.com/en/32650-90854/ch12s09.html
http://docs.hp.com/en/B2355-90053/ch01s04.html

If you have any specific questions re: h/w paths and fabric, post it here.

-denver

Re: hardware paths

geeta — Tue, 25 Oct 2005 20:24:06 GMT

very helpful..thanx. the second link infact is perfect! lets see how the training goes tom and i am sure i will be back with more :) thanx again

Re: hardware paths

Arunvijai_4 — Wed, 26 Oct 2005 00:15:04 GMT

Hi Geeta, If this is useful, you can assign points to posts and close the thread.

http://forums1.itrc.hp.com/service/forums/helptips.do?#28

-Arun

Re: hardware paths

geeta — Wed, 26 Oct 2005 19:26:03 GMT

And more frm the training class!

How do we figure out a LUN # frm something like this: c0t0d0? And how would it be different for a scsi and fibre channel system?

The h/w path seems to be more clear now, so thanx everybody for helping me out on tht:)

Re: hardware paths

Granite — Wed, 26 Oct 2005 19:38:55 GMT

Hi Geetha,

Think a DOT in the link last may took you to an missing URL..my above links..

Back to the track..LUN is just a logical space you are assigning to the server from any disk-array/JBOD/storage. Ideally, server will see a LUN as one single unit(c#t#d#) as like a disk.

root-/>ioscan -funC disk |pg
Class I H/W Path Driver S/W State H/W Type Description
==========================================================================
disk 0 0/0/1/0/0.6.0 sdisk CLAIMED DEVICE HP 36.4GST336706LC
/dev/dsk/c0t6d0 /dev/rdsk/c0t6d0
disk 273 0/0/3/0/0.4.0 sdisk CLAIMED DEVICE HP 73.4GST373307LC
/dev/dsk/c1t4d0 /dev/rdsk/c1t4d0
disk 2 0/0/3/0/0.6.0 sdisk CLAIMED DEVICE HP 36.4GST336706LC
/dev/dsk/c1t6d0 /dev/rdsk/c1t6d0
disk 305 255/255/0/3.3 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c21t3d3 /dev/rdsk/c21t3d3
disk 306 255/255/0/3.4 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c21t3d4 /dev/rdsk/c21t3d4
disk 385 255/255/0/4.6 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c21t4d6 /dev/rdsk/c21t4d6
disk 386 255/255/0/4.7 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c21t4d7 /dev/rdsk/c21t4d7

I can map from the "Description" column to find the LUNs from where it has been assigned to server.Here"COMPAQ" is my SAN and "HP ..." are my int.disks.

regds,granite

Re: hardware paths

geeta — Wed, 26 Oct 2005 19:57:00 GMT

Hi,

no worries about the link u sent earlier..:)
however, whtu j ust explained kinda makes sense as far knowing wht the c#t#d# stand for..But i am still not clear on how to figure out what kind of device wehave by looking at such info? And also in class today wht we were doing was multiplying 'd' by 1 't' by 8 and c is the 128th place for example in c5t0d0 the lun # is d*1 t*8..and so on???? I have no idea how thts done ! Sorry about the trouble but I am new to all this and I just trying to keep pace with my class. I understand the concept of the whole scsi fibre thing but these calculations ---i need help !!

Re: hardware paths

geeta — Wed, 26 Oct 2005 20:04:53 GMT

And also lets take this example :

8/12.8.0.255.0.1.0 sdisk CLAIMED DEVICE DGC C3400WDR5

The example above is the hardware path of LUN0 of a directly attached Fibre Channel Mass Storage device with Loop ID of 1

how do we know its LUN 0 and tht the loop id is 1?

Re: hardware paths

Granite — Wed, 26 Oct 2005 20:05:10 GMT

Hi geetha,

The multiplication wat u said is to find the LUN ID using the hardware path.
Ex;disk 385 255/255/0/4.6 sdisk CLAIMED DEVICE HSV110 (C)COMPAQ
/dev/dsk/c21t4d6 /dev/rdsk/c21t4d6.

For the above disk,the LUN ID is (128*0)+(4*8)+6 = 38.
Just take the last serials from your hardware path.

Regds,Granite.

Re: hardware paths

geeta — Wed, 26 Oct 2005 20:10:53 GMT

ok tht helps.then wht about the fibre stuff? why is it LUN 0 in the fibre example i pasted in the last question?

Thanx Granite :)

Re: hardware paths

Hoang Chi Cong_1 — Wed, 26 Oct 2005 21:31:13 GMT

Hi
Let check the attachment.
You will know why :)

Regard,
Hoang Chi Cong