Specifications

Chapter 6. Multiple zPDT instances 79

# su ibmsys1

$ cd /home/ibmsys1

$ awsstart aprof1 working as ibmsys1

(startup messages) ibmsys1 instance

$ x3270 -port 3270 mstcon:localhost & working as ibmsys1

$ x3270 -port 3270 tso:localhost & working as ibmsys1

$ ipl a80 parm 0a8200 working as ibmsys1, IPL z/OS

(open another terminal window)

# su ibmsys2

$ cd /home/ibmsys2

$ awsstart profSB working as ibmsys2

(startup messages) ibmsys2 instance

$ x3270 -port 3271 localhost & working as ibmsys2

$ ipl 200 working as ibmsys2, IPL VM

Each instance is started with its own devmap. Each devmap must specify a different port

address for local 3270 connections. Each instance must specify different emulated disk

volumes. Attempting to share an emulated disk volume in this situation (by specifying the

same Linux file for the emulated volume) will result in corrupted data on the volume.

The use of xhost + presents a security exposure; you should tailor this command to suit your

security environment

6.4 Instances with shared I/O

It is possible for multiple instances to share certain devices, such as emulated DASD and

emulated OSA. Also, a single pool of 3270 devices can be used and accessed via a common

Linux port number, although this option has more complex side effects. The most common

use of a shared configuration is to provide shared DASD among the instances.

Please note that zPDT does not support the VMAC function of z/OS. The only virtual mac

supported is generated on z/VM with the layer-2 vswitch.

A configuration with shared I/O devices requires a group controller; see Figure 6-3. The group

controller is similar to another zPDT instance, but without an associated CP or memory. The

group controller must have its own Linux userid, its own devmap, and be started with its own

awsstart command. It must be started before other instances are started. As a basic concept,

the I/O devices defined in the group controller’s devmap are inherited and shared by the other

instances.