topic Re: Device path explain? in Operating System - HP-UX

Device path explain?

seenivasan — Wed, 27 Oct 2010 06:33:12 GMT

Dear Team

disk 3 1/0/6/1/0/4/0.8.0.255.0.0.0 sdisk CLAIMED DEVICE HPQ BF03658242

/dev/dsk/c4t0d0 /dev/rdsk/c4t0d0

Explain above device path breifly?

Re: Device path explain?

Chandrahasa s — Wed, 27 Oct 2010 06:57:29 GMT

Hi,

proivide model and uname -a out put.

Chandra

Re: Device path explain?

Torsten. — Wed, 27 Oct 2010 09:11:11 GMT

Without

# model

and

# ioscan -fn

I can only tell it is a fiber channel loop connected disk.

Re: Device path explain?

Matti_Kurkela — Wed, 27 Oct 2010 15:22:30 GMT

Hardware path: 1/0/6/1/0/4/0.8.0.255.0.0.0

This looks like a hardware path from a nPar-capable server. So the first four numbers can be used to identify the PCI slot. Run "rad -q" or "olrad -q" (depending on your HP-UX version) to get a list of device path components and the corresponding PCI slot numbers.

1 = cell #1
0 = system bus adapter
6 = local bus adapter
1 = PCI device number

0/4 = unknown; probably indicates this is a multi-port or multi-function PCI card.

0 = card port #0

8.0.255.0.0.0 = a FibreChannel device path; structure is Domain.Area.Port.Bus.Target.LUN.

Domain 8 indicates Private Loop addressing, so this FC HBA is not connected to a SAN fabric, but only to stand-alone FC disk box(es). In Private Loop mode, the Area is always 0.

Port 255 indicates Peripheral Device Addressing mode is used. In this mode, the FC Loop ID = (Bus * 16) + Target, or 0 in your case.

In Peripheral Device Addressing mode, the LUN field is simply the target disk/LUN number.

To summarize:
This is probably the first disk or LUN in an external FibreChannel-connected storage box, connected to FC port 0 of a FibreChannel HBA located in slot identified by hardware path 1/0/6/1.

If the "rad -q" / "olrad -q" listing identifies the slot by a dash-separated four-digit string (like A-B-C-D), then the first digit is the cabinet number, second is the side (0 = front, 1 = back), third is the I/O box number, and the fourth is the slot number in that I/O box.

MK

Re: Device path explain?

Torsten. — Wed, 27 Oct 2010 19:21:04 GMT

In the beginning (e.g. E-class servers) the rules for device paths were very strict, but later they became a bit more individual.

So without knowing the server model you cannot tell anything for sure.

The path "1/0/6/1" can be found on many different servers, cell-based and non cell-based, perhaps even non-hotswap (so you cannot get details by using "olrad" commands).

Tell your server model ("model" command)and provide an "ioscan -fn" and we can provide you more details.

The part of the path "8.0.255" indicates it is using fiber channel in loop mode, so you probably use a FC connected disk chassis like DS2405 or DS2500 or FC10 or something - this will be shown in the ioscan.

BTW, did you already read this?

http://forums11.itrc.hp.com/service/forums/helptips.do?#33

Re: Device path explain?

P Arumugavel — Thu, 28 Oct 2010 03:34:46 GMT

Hi,

Use the lssf command to display detailed information about a device file.

#lssf /dev/rdsk/c4t0d0

Regds \ Vel

Re: Device path explain?

Ismail Azad — Thu, 11 Nov 2010 21:24:02 GMT

Hi mr. seenivasan,

/dev/dsk and /dev/rdsk are block and character device files respectively in legacy fashion. c stands for controller, t for target and d for the lun or disk. The controller is 7 bit , the target is 4 bit and the lun is 3 bit. Hope this is useful!! Cez of what i understood you were interested in device file naming as well including the H/W path.

Regards

Re: Device path explain?

Torsten. — Thu, 11 Nov 2010 21:34:03 GMT

@seenivasan: Do you still join this (your) thread?