topic Re: Device instance numbers in ioscan output in Operating System - HP-UX

Device instance numbers in ioscan output

pmcenery — Mon, 24 May 2010 12:14:12 GMT

Hi.

On our system we have replaced the SAN fabric and therefore all of the original paths to the disks are no longer present. After the fabric was replaced, I went through the following procedure to regain access to the disks:

- vgexport (all san based volume groups)
- for i in $(ls /dev/dsk); do rmsf -a $i; done
- ioscan -fnC disk
- insf -e -C disk
- vgimport (using map files)

This all worked successfully, but I noticed that in an `ioscan' output, the disk instance numbers ("I" column) seem to have skipped the original disks which are no longer visible. I am guessing that these are somehow still "defined" somewhere in the system. See the following `ioscan' output:

Class I H/W Path... Description
===================================
disk 1 0/0/2/0....
disk 2 0/0/2/0....
disk 473 0/2/0/0....
disk 474 0/2/0/0....
[...]

Notice that the instance numbers start at 473. Before the SAN fabric was changed, they carried on from instance number 2 sequentially (i.e. 3, 4, 5, etc.).

Is there a way that I can "remove" the definitions of these "invisible" disks and rescan?

Any advice would be much appreciated.

Thanks in advance.

Re: Device instance numbers in ioscan output

Steven E. Protter — Mon, 24 May 2010 12:27:11 GMT

Shalom,

try using rmsf on the offending device files.

SEP

Re: Device instance numbers in ioscan output

TTr — Mon, 24 May 2010 12:40:45 GMT

You have to go through a ioinit device instance renumbering exercise. Search in these forums for "ioinit", "ioconfig" for details. These two threads might have everything you need.
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=425790

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=26117

Re: Device instance numbers in ioscan output

singh sanjeev — Mon, 24 May 2010 12:45:20 GMT

#rmsf -H
or
#rmsf -a

remove it also from if you have used EMC power path

#powermt remove dev=c?t?d?
#powrmt check
#powermt save

Re: Device instance numbers in ioscan output

Michael Steele_2 — Mon, 24 May 2010 12:45:55 GMT

Hi

If ioscan can see them then they are still active and being exported to your server from the disk array.

Verify that the disk array is configured properly and then rmsf.

Don't ioinit. This is unnecessary.

Re: Device instance numbers in ioscan output

pmcenery — Mon, 24 May 2010 13:11:07 GMT

Thank you for all the replies.

A couple of notes:

1. ioscan can no longer see the "invisible" devices.

2. /dev/dsk/* and /dev/rdsk/* have been rmsf'd.

The instance numbers still somehow seem to be in use and are not reused. Are there some other /dev/??? devices that I should have removed?

I even tried doing rmsf -k -H (for each hba).

From what I can tell, the ioconfig approach seems to be the way forward. I'm assuming you need actual console access if you intend to rename /etc/ioconfig and /stand/ioconfig before shutting down the system.

Many thanks.

Re: Device instance numbers in ioscan output

Kevin Wright — Mon, 24 May 2010 20:52:20 GMT

correct.. but the instance numbers used really is meaningless from an operational standpoint. If you like them all numbered in order, you need to run ioinit, otherwise, why bother?

Re: Device instance numbers in ioscan output

chris huys_4 — Mon, 24 May 2010 21:52:45 GMT

Hi,

Leave it like it is. You shouldnt try to fix something, that isnt broken, well not in this case at least.

Even the rmsf in the procedure isnt necessary, the OS doesnt care about the obsolete device files, therefor you shouldnt either.

Greetz,
Chris
PS. The only thing that is missing from the procedure is a reboot of the system once the san paths were changed.

Re: Device instance numbers in ioscan output

Duncan Edmonstone — Tue, 25 May 2010 05:38:17 GMT

The _only_ reason you should consider going through the ioinit rigmarole is if you are on 11.11 or 11.23 and running out of ext_bus instance numbers.

You only get a maximum of 255 ext_bus instance numbers in 11.11 and 11.23, and if you have moved your LUNs around a _lot_ and have a _lot_ of LUNs it is possible to hit this limit. You can check how high you are now in ext_bus instances using:

ioscan -kfC ext_bus

HTH

Duncan

Re: Device instance numbers in ioscan output

pmcenery — Tue, 25 May 2010 09:20:34 GMT

Many thanks for all the replies.

I have decided not to go through the process of an ioinit, but I now know what needs to be done if I wanted to regain the missing instance numbers.

Regards,
Paul.