topic Re: HIghest instance number in Operating System - HP-UX

HIghest instance number

kw_1 — Mon, 28 Apr 2003 12:19:44 GMT

We have large amount of disks on our HP-UX 11i systems. Because we are troubleshooting/re-configuring disk assignments, we are re-ioscanning over and over many times. Does anyone knows what is the highest instance number it can be and what will happen if that limit is exceeded?

Re: HIghest instance number

Steve Steel — Mon, 28 Apr 2003 12:47:54 GMT

Hi

For more information, see man "insf(1M), lssf(1M), mksf(1M), rmsf(1M)" ,Your O/S release Notes and the "Configuring
HP-UX for Peripherals" manual.

www.docs.hp.com

Steve Steel

Re: HIghest instance number

Sachin Patel — Mon, 28 Apr 2003 12:49:20 GMT

I don't know the highest number but we have instance number upto 110 in one of our server.

Sachin

Re: HIghest instance number

Dietmar Konermann — Mon, 28 Apr 2003 13:07:37 GMT

See page 2 of:
http://www.docs.hp.com/hpux/onlinedocs/netcom/maxlun-whitepaper-v1.0.pdf

Best regards...
Dietmar.

Re: HIghest instance number

Bill McNAMARA_1 — Mon, 28 Apr 2003 13:11:06 GMT

depends on the hardware configuration more than software. Under FC you can get in the order of 16Million theoretically addressed or something crazy like that, but in reality it's what you're busses support.

cXtYdZ
c 7bits = lots of ext_bus'es
t 4 bits = 16 targets
d 3 bits = 8 luns
for SCSI busses.
(FC targets overflow >4bit t fields into the c field)

Later,
Bill

Re: HIghest instance number

Lorenzo Facello — Mon, 28 Apr 2003 17:59:05 GMT

Hi,
Have you try to launch:
insf -e
to reinstall all the device file.
Take a look also at the man pages to find other options.

L.

Re: HIghest instance number

Bill Hassell — Mon, 28 Apr 2003 18:36:22 GMT

As you delete disks or LUNs, be sure to use rmsf to remove the device files (not rm /dev/dsk..whatever...) as this will remove the instance from the kernel and allow that instance to be reused.

Alternatively, you can specify a given (unused) instance number using insf -I

Hint for systems with a lot of devices: ioscan -k will always give instant response without polling every device on the system. The only time you'll need to drop the -k is when you add devices while the system is running (which is a bit risky anyways).

Re: HIghest instance number

kw_1 — Mon, 28 Apr 2003 19:01:54 GMT

I apologize for not being more specific with my question. By instance number, I meant the second column of the output from "ioscan -f". Our current highest number is 267 so I assuming we're safe to at least 512. Unless there is a limitation problem, we probably won't take any steps to re-assign any numbers.