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Change scsi ID

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Kelli Ward
Trusted Contributor

Change scsi ID

Hi all,
I have a system that was built with a scsi id of 5. I need the system to boot from scsi address 6 and yes you guessed it, it is LVM. How do I change to boot address in the system without rebuilding the drive?
Thanks,
Kel
The more I learn, the more I realize how much more I have to learn. Isn't it GREAT!
10 REPLIES
erics_1
Honored Contributor

Re: Change scsi ID

Kelli,

You could use the setboot command.

setboot -p [Hw path] -b on

Regards,
Eric
Craig Rants
Honored Contributor

Re: Change scsi ID

The standard boot disk is usually id 6 so at some point the boot was changed. You have two answers to your one question.

First, use setboot to change which drive to boot from.

Second, if you have another empty disk in id 6, mirror the disk in 5 to 6, then break the mirror and leave the disk in 6 as the primary.

** This assumes that you have MirrorDisk/UX and OnlineJFS, as well as a free disk in id 6.

Otherwise your problem will require you to use setboot, shutdown the server, move the disk, and then reboot.

I think option one is the easier.

Of course you will probably get some more ideas from other contributors.

GL,
C
"In theory, there is no difference between theory and practice. But, in practice, there is. " Jan L.A. van de Snepscheut
Kelli Ward
Trusted Contributor

Re: Change scsi ID

I don't quite think that is what I'm looking for. Right now, I have a drive that boots HP-UX on address 5. If I were to change it to address 6 and boot it, it would crash for an LVM error because the vg is connected to the device file at address 5. However, I want to boot it from address 6. So, I need to know how to set it to do this. I believe setboot only sets the boot path in firmware, unless there is something I am missing.
Please let me know.
Thanks,
Kel

The more I learn, the more I realize how much more I have to learn. Isn't it GREAT!
Kelli Ward
Trusted Contributor

Re: Change scsi ID

Hi,
The guys who built it, inadvertantly did so from address 5. They would like to change it to address 6 without rebuilding the drive. It is my understanding setboot does a firmware of stable store change, but what I really need is to tell the operating system the drive it should be booting from is 6. Can I do this without building it again?
Thanks,
Kel
The more I learn, the more I realize how much more I have to learn. Isn't it GREAT!
Patrick Wallek
Honored Contributor
Solution

Re: Change scsi ID

So, are you saying the the OS was originally installed on the drive with SCSI ID 5, but you now need it to be installed on the drive with SCSI ID 6?

Or are you saying the drive itself was installed at 5 and now needs to be changed to 6?

If it is the first, then it will probably be easier to reinstall on the drive at SCSI ID 6. If you have a tape drive on this machine you can create a make_tape_recovery tape, then boot from the tape, change the root disk to the one at id 6 and let it rebuild your machine.

If the drive itself needs to changed from ID 5 to ID 6, then you still need to reinstall as there are VG and LV structures that look at the device file, which would change with the ID change.
Kelli Ward
Trusted Contributor

Re: Change scsi ID

Hi Patrick,
Your second scenario is the correct one.
What it sounds like is there is no protocol for changing the HW address of the drive once it is set and have it successfully boot without crashing the LVM. (That is without reinstalling the OS.) I have seen it done successfully from an interactive ignite session from a boot tape, but again that required a reinstall of the OS. I was hoping for a faster solution.
FYI for me question. What other files besides /etc/lvmtab does the file system reference /dev/vg00 to /dev/dsk/c#t#d# on your root disk?
Points to follow.
Thanks to all for the info.
More info is always welcome.
Kel
The more I learn, the more I realize how much more I have to learn. Isn't it GREAT!
Bill Hassell
Honored Contributor

Re: Change scsi ID

There are many places which would have to be carefully changed (and not simple vi) with a less 50:50 chance of getting everything right. Instead, make an Ignite/UX backup using make_tape_recovery. Then change the drive SCSI ID and restore interactively (pick the VG00 target disk).

Or you can decide whether a simple SCSI address is worth changing...


Bill Hassell, sysadmin
Kelli Ward
Trusted Contributor

Re: Change scsi ID

Unfortunately, this system does need a specific address due to it's use. I was just hoping for a two minute command line solution instead of a 45 minute reinstall. (Good for future reference to, since this is not the first time I've heard of this.) That's okay though, I'll just make the guys who built it, rebuild it. ; )
Thanks all,
Kel
The more I learn, the more I realize how much more I have to learn. Isn't it GREAT!
harry d brown jr
Honored Contributor

Re: Change scsi ID

Kelli,

Good idea to have the ones "broke it" "fix it"!

kelli, you made a comment that your application is looking for a specific disk drive, for what reason would anyone do such a thing? I'm just wondering why, not being nasty :-)

live free or die
harry
Live Free or Die
Kelli Ward
Trusted Contributor

Re: Change scsi ID

No problem Harry,
Very simply this is one of a number of test/repair systems that have test scripts run on them through a central server. The systems need to be as matched as possible for ease of testing and programming.
Thanks,
Kel
The more I learn, the more I realize how much more I have to learn. Isn't it GREAT!