Alan,
We use the same device number for each CEC that is sharing a device.
Other CEC's, or other channel sets on the same CEC, might use that
device number for another device. E.g. there might be 3 different DASD
volumes at device number 2000 in the data center, but every LPAR that
accesses a given volume uses 2000. For tape, we try not to reuse device
numbers for different drives.
For CTC's, every LPAR has a target CTC address range. Any other LPAR
that wants to connect with a given target uses the same address to
connect to it. Generally, each LPAR has two ranges of 16 devices as its
target, to allow for send/receive pairs and redundancy.
Dennis O'Brien
"Don't worry about biting off more than you can chew. Your mouth is
bigger than you think." -- CVW-11 chaplain, "Carrier"
-----Original Message-----
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On
Behalf Of Alan Altmark
Sent: Friday, May 30, 2008 06:33
To: [email protected]
Subject: [IBMVM] Real device number assignments
Pop quiz:
For those of you who have multiple boxes (CECs) sharing devices, do you
assign the same device number in the IOCDS to the device for each CEC?
Example: Given a shared 3390 volume, if it is known as device number
800
on CEC A, do you assign it device number 800 on CEC B?
If you don't do that, what device numbering scheme do you use?
Alan Altmark
z/VM Development
IBM Endicott
