Hardware addressing Device / Function

[ben10_1]

I have 3 disk on HPUX 11iV2 the ioscan -k shows:
0/1/1/0.0.0 disk HP 36.4GST336753LC
0/1/1/0.1.0 disk HP 73.4GMAU3073NC
0/1/1/1.2.0 disk HP 36.4GST336753LC

We can see the "Device/function" in the HW address is 1/0 for the first 2 disks and 1/1 for the third.

Should I have the same device/funtion number for the 3 disks? Since all the disks have the same function and the same device type?

I will be glad if anyone can clarify this.

[Duncan Edmonstone]

The hardware path _does not_ contain any information to speak of which defines a devices function or type - why did you think that? More typically the device type would be associated with the major number of the device file for the device.

Still we can probably explain what you see if you can tell us the model of the system.

HTH

Duncan

[ben10_1]

The system I am experimenting on is:rx2600 11iv2
Actually I am trying to understand and figure out the Legacy HBA HW addressing, Cell/SBA/LBA/Device/Function

So what do they mean with Device/Function?
I couldn't find a clear explanation.

[Noé]

Hi.

Perhaps in this site web you can find the information you need (I think it is very understandable with several figures):

http://www.kumanov.com/docstore/manuals/hp-ux/en/T1335-90098/ch08s01.html

Regards.

[Duncan Edmonstone · Accepted solution]

In the case of the rx2600 0/1/1 is the internal IO controller which has 2 SCSI buses on it, so:

0/1/1/0.0.0 disk HP 36.4GST336753LC
0/1/1/0.1.0 disk HP 73.4GMAU3073NC

are on one SCSI bus and:

0/1/1/1.2.0 disk HP 36.4GST336753LC

Is on the other SCSI bus

The rx2600 is not a cell based system so there is no cell component to the HW path. In this case the "device/function" definition below the LBA simply shows you where LBAs have multiple devices using an internal PCI bridge on the card. You would see something similar on any card with more than 1 port/connector on it (e.g. a dual port FC card or a quad-port LAN card or a FC/LAN Combo card).

HTH

Duncan

[ben10_1]

Thank you Duncan,

Is there a table that shows what the Device/Function mean ?

In other word:
0/0 = one device using internal PCI bridge
0/1 = 2 devices using internal PCI bridge
..........................


And please correct me if I am wrong.

[Duncan Edmonstone]

I don't think there is any particular "standard format" you can apply here... for example here's an ioscan output for a FC/GbE combo card:

ba 4 0/4 lba CLAIMED BUS_NEXUS Local PCI-X Bus Adapter (12ee)
ba 5 0/4/1/0 PCItoPCI CLAIMED BUS_NEXUS PCItoPCI Bridge
fc 0 0/4/1/0/4/0 fcd CLAIMED INTERFACE HP AB465-60001 PCI/PCI-X Fibre Channel 2-port 2Gb FC/2-port 1000B-T Combo Adapter (FC Port 1)
fc 1 0/4/1/0/4/1 fcd CLAIMED INTERFACE HP AB465-60001 PCI/PCI-X Fibre Channel 2-port 2Gb FC/2-port 1000B-T Combo Adapter (FC Port 2)
lan 2 0/4/1/0/6/0 igelan CLAIMED INTERFACE HP AB465-60001 PCI/PCI-X 1000Base-T 2-port 2Gb FC/2-port 1000B-T Combo Adapter
lan 3 0/4/1/0/6/1 igelan CLAIMED INTERFACE HP AB465-60001 PCI/PCI-X 1000Base-T 2-port 2Gb FC/2-port 1000B-T Combo Adapter


As you can see - different from what you see... all you can really do in these cases is know that everything below the LBA level is generally on a single card in a PCI/PCI-X/PCIe slot

HTH

Duncan

[Torsten.]

The hardware path is like a tree of hardware.

For this machine, the root is the main I/O chip - the system bus adapter. From there it goes to another I/O controller chip, where the dual channel scsi adapters are connected. This all is located directly on the system board.

The first scsi channel has the lower 2 internal disks connected, the other channel has the upper disk and the external scsi connector.

So if you see this

0/1/1/0.0.0 disk HP 36.4GST336753LC
0/1/1/0.1.0 disk HP 73.4GMAU3073NC

it means in this case

ioa 0 0 sba CLAIMED BUS_NEXUS System Bus Adapter (1229)

ba 1 0/1 lba CLAIMED BUS_NEXUS Local PCI-X Bus Adapter (122e)

ext_bus 2 0/1/1/0 mpt CLAIMED INTERFACE SCSI Ultra320
/dev/mpt2

and finally the both disks with scsi address 0 and 1.

[Matti_Kurkela]

By themselves, the Device/Function numbers don't tell anything at all about the type of the device, but only about its logical position in the system. For the type information, you should be looking at the "Class", "Description" and "Driver" fields of the ioscan output.

For example, the first disk in your initial post has hardware path 0/1/1/0.0.0. This is a path for a SCSI disk, so drop out the last two numbers (target & LUN) and you get the hardware path of the SCSI controller that drives the disk. That's 0/1/1/0.

The hardware path numbers start from 0, so starting from the right and working towards the left, this device is the first function (function 0) of the second device (device 1) of the second LBA (LBA 1) of the first SBA (SBA 0).

In this case, the device 0/1/1 is the integrated SCSI controller. It has multiple SCSI buses, presented as separate functions: each function is a separate SCSI bus in this case. Those SCSI buses will be 0/1/1/0 and 0/1/1/1. If this controller had a third SCSI bus, it would be 0/1/1/2.

If you see another SCSI controller with hardware path like 0/1/? (e.g. 0/1/2 or 0/1/5), then you know this controller is attached to the same LBA as the system disks, so it uses the same PCI bus as the system disks. If you plug a high-bandwidth device to that controller, you might start seeing I/O bottlenecks with system disks.

But if the other SCSI controller has a hardware path like 0/2/?, you know it connects through a different LBA, so it would be a better choice for connecting a high-bandwidth Ultrium 4 tape drive, for example. A hardware path that indicates a different SBA (like 1/0/?) would be even better, as its I/O path would be as separate as possible from the system disks.

Each SBA has its own set of LBA numbers, each LBA has its own set of device numbers and each device has its own set of function numbers. Your first and second disks' hardware paths are identical up to and including the function number: that means those two disks are plugged into the same SCSI bus.

MK

[Torsten.]

About 15 years ago there was a clear rule for the hardware pathes based on the slot number where a HBA is installed. This was the time of E-class servers where the pathes starts with high numbers like 52 or 56 because of the rule.

But later the rule was no longer valid, so at the end each server has its own unique hardware tree with own unique rules to build this path.

You need to know the server model, look up the pathes in the manual and then you can be sure where the unit in question really is.



An example:

43/0/2/2/0/0/0/4/0/0/1

this is a fibre channel port on a multi function HBA installed in an IO extender connected to the new superdome 2.

By knowing this background, you can tell where exactly this HBA is (IO extender chassis number and slot) - without this background, it is just a number.