ioscan & insf command question

[Vinay Narayana]

I have a HP 11i host to which I allocate new devices quite regularly. So each time I allocate the devices I run `ioscan -fnC disk` command and the newly allocated device becomes visible to the host. But sometimes I have to issue `insf -e -C disk` for the host to recognize the new devices. I dont know why this happens.

I want to know 2 things:
1. Why doesn't HP need the insf command all the times?
2. Is issuing the above insf command in a multi-user mode recommended? I always issue the command in a multi-user mode and Iam yet to see any problem with that.

Thanks
Vinay

[SS_6]

ioscan is to scan hardware and insf is to create device files. There is no harm to run this in multiuser mode. I have used this command so many times as we have to allocate disks from XP time to time. Do man on both commands for more informatioin.

[Sundar_7]

I have never seen my device files automatically created after ioscan - HP-UX always would require insf unless u had a reboot of the system.

1. As far as I know, HP-UX requires ioscan followed by a insf to recognize new devices

2. Issuing insf in mutiuser mode is absolutely fine. It does nothing destructive.

[Jeff Schussele]

Hi Vinay,

To answer your questions:

1) IF the device already exists then you won't need the insf command. For instance /dev/dsk/c12t6d4 *was* in use months ago & then was no longer there AND you hadn't used rmsf to remove it. Then if a new LUN is presented & it's c12t6d4 then you wouldn't have to insf the new device into existence.

2) Yes - it's allowed. But you really don't need any parameters on insf - the command alone will create the newly discovered devices.

HTH,
Jeff

[SS_6]

sometimes if old device file is present but not the physical, it will be used by new device. using -C (particular device class) is always useful and it only look for those devices.

[Vinay Narayana]

Thanks All for your replies.

The reason I was concerned about issuing the insf command is because the man page for insf states the below:

"WARNINGS insf should only be run in single-user mode. It can change the mode, owner, or group of an existing special file, or unlink and recreate one; special files that are currently open may be left in an indeterminate state.
Many commands and subsystems assume their device files are in /dev, therefore the use of the -D option is discouraged."

So do you all think I can safely disregard this message.

[SS_6]

Vinay, I understand what you are after. No, we never ignore any vendor,s warnings but practically as I told my experience I have done it many times and no issues and I also I think it is not easy to bring production servers down every time just to allocate disks.