topic Why did HP use the switch port number to create device files? in HPE EVA Storage

Why did HP use the switch port number to create device files?

Thomas J. Harrold — Sun, 02 Jun 2002 05:12:52 GMT

Is there a good technical reason why HP creates the devices files based on switch domain ID and port number? It would certainly be nice to be able to move a cable to any port (say if a port fails...), and not have to export/import.

-tjh

Re: Why did HP use the switch port number to create device files?

Paul Barmettler — Mon, 03 Jun 2002 08:26:08 GMT

Hi Thomas,

this behavior is not an invention of HP.
It's part of the Fibre Channel Protokoll (FCP).

Bye

Re: Why did HP use the switch port number to create device files?

Insu Kim — Tue, 11 Jun 2002 14:10:42 GMT

HPUX is a hardware path oriented operating system.

When HPUX is booting, it does an ioscan and compares the hardware path information to what is stored in the
/etc/ioconfig file.
If it finds a match, it will assign the instance number in the /etc/ioconfig file to the matching hardware path.
If it does not find a match, it will assign the next available instance number to the path. This permits
the system to maintain the same instance numbers across reboots of the system.

If software address is allowd, these hardware paths and their associated device files could change at any time.
To avoid this, soft address is not allowed by the HPUX FC driver.

Hope this helps,