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SCSI bus addressing in 5.1x

Leonardo_9
Occasional Visitor

SCSI bus addressing in 5.1x

Please i would like to know if it's possible to change the scsi bus of an adapter in Tru64 5.1B. I mean, in the earlier versions 4.0x it was possible to change the scsi bus number in the configuration file. Now in 5.1x there is no reference about bus number in the config file. Where i can change it?!!
My problem is: i have an emx0 adapter which scsi bus is 1"scsi1 at emx0 " and i need to change to scsi0.
Thanks for any help
7 REPLIES
Hein van den Heuvel
Honored Contributor

Re: SCSI bus addressing in 5.1x

The whole device naming is overhault in 5.1.
Your scsi disks will show up as dsk1, dsk2...
This dsk assignments are more or less permanent
and survive basic device removal/addition.
The underlying structure is now a WWID and HWID.
The change was make to make clusters more robust/flexible: afterall, the same bus-lun-target (BLT) could refer to different drives if the hardware layout for each member is not identical.
The bus-lun-target is driven to the background.
It can still be visualized through hwmgr:
Notably: hwmgr -show scsi
But also: hwmgr -view hierarchy

Now WHY do you care about specific disk names?
That is 'so retro', and do unreliable (add an adapter and poof!.
Even for say 'raw devices' you can surely still play with smoke and mirrors (soft-links) to achieve independence from physical names no?

Good luck,
Hein.

Leonardo_9
Occasional Visitor

Re: SCSI bus addressing in 5.1x

Hi Hein, thank you for your response. But i'm having problems with EDM from EMC. And the EMC's people are saying that the problem is that. In one cluster member dsk0 is on bus 0 and in the other member dsk0 is on bus 1. So, to prove them there is no problem with that, i would like to change the scsi bus from one of the members. Did you understand what i'm saying?!!
When the machine boots, that message:
"scsi1 at emx0 at pci0 .... "
i want to know from where the emx driver takes or assigns the bus number "scsi1". I want to change to scsi0. Only for tests and to prove to EMC's people the problem is another issue.
Thank you,

LEONARDO
Ralf Puchner
Honored Contributor

Re: SCSI bus addressing in 5.1x

EMC is not directly supported by HP, EMC is supported by EMC. If you need support for Tru64 and your storage buy HP storage!

Tru64 5.x doesn't care about scsi busses because the disks are location via WWID. We do not have an restriction or problem using different busses in this version of TruCluster or Tru64 because the disks are found automatically if changing the physical location.

One possiblity to change the bus location is to change the driver include statement within the /usr/sys/conf/HOSTNAME kernel konfiguration file. Move the driver statement to the end of the file may solve your problem. Don't forget to rebuild your kernel.





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Leonardo_9
Occasional Visitor

Re: SCSI bus addressing in 5.1x

Guys, if what i'm asking isn't support or if you don't know the answer, please simply say it!!!!
It doesn't matter if the storage is EMC or HP or whatever!!! I want to change the scsi bus number for the emx0 adapter!!!!
Is it possible or not?!!
Thank you,

LEONARDO
Hein van den Heuvel
Honored Contributor

Re: SCSI bus addressing in 5.1x

I want to change the scsi bus number for the emx0 adapter!!!!
Is it possible or not?!!

Yes, but only with a screwdriver.

You will have to physically move the interface in the PCI slots. You may have to add interfaces to compensate for internal interfaces.

Hein.
Ralf Puchner
Honored Contributor

Re: SCSI bus addressing in 5.1x

Leonardo,

I you have read my answer then have a closer look to the last paragraph for the solution of your problem.

It is important, because HP guarantees and tested that HP storage "will" work, in case of EMC it "could" work. And that is the difference, giving you a clue who is responsible to get it working....
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Dave Bechtold
Respected Contributor

Re: SCSI bus addressing in 5.1x

Hi Leonardo,

I will attempt to answer your specific questions.

Is it doable?

Yes and No, it's dependent on the following:

- System model, hardware architecture and it's implementation of embedded SCSI buses in the system. Example: if the system has 2 embedded SCSI buses, EIDE/ATA (ata) and QLogic (isp), like a Digital Personal Workstation 600, those controllers will be represented as scsi0 (ata0), scsi1 (ata0), and scs2 (isp0). If an optional PCI HBA was added to the system it would be scsi2. The scsiN bus assignment is based on which controller was probed and discovered first.

- The SCSI HBA option model (Single Channel versus dual), dual channels show as 2 separate SCSI busses.

- The position of the PCI HBA option relative to the CPU - electrically closest. Those embedded on the system I/O motherboard etc... will be scsi0 and so on, then those in the PCI bus slots PCI0 then PCI1.

So, depending on your system model/architecture and HBA model you may or may not be able to achieve the desired results.

Trying to remove names from the hardware database would also not probably be fruitful since on reboot it's going to name controllers as they are discovered on boot, unless you rename the driver_config entry also and delete the entries (hwid's) from the database - this get's very tricky and dependent on your systems configuration.

I have not had success with SCSI HBA's and re-ordering config_driver statements in the systems configuration file. The config file causes the kernel to load the required drivers and not effect the probing and discovery of the HBA's.

A posting of the systems "hwmgr -view hier" would help nail this down.

Hope that helps.

Regards,
Dave Bechtold