z/VM Guest LAN type setup

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The z/VM® guest LAN feature provides support for network connection of guest machines. Guest LANs can be used for TCP/IP communication between guests or between guests and a z/VM TCP/IP service machine.

A VM guest LAN can only support connections to virtual machines on the same VM system. The z/VM configuration used in this study defined two guest LANs, one for the DMZ and the other for the internal zone. A guest LAN can either simulate a QDIO LAN or a HiperSockets™ LAN. For HiperSockets, the MFS specified on the guest LAN definition is also important. The MFS can be defined for the guest LAN as 16 KB, 24 KB, 40 KB, or 64 KB.

The following z/VM commands were used to define the guest LANs:

for HiperSockets:

'cp def lan vlan1h owner system type hiper mfs xxk'  
'cp def lan vlan2h owner system type hiper mfs xxk'

for QDIO

'cp def lan vlan1 owner system type qdio' 
'cp def lan vlan2 owner system type qdio'

The guest LANs included in our tests were intended to have no access to an OSA card because this was an isolated network and the only access from the external LAN to the WebSphere® Application Server was through the DMZ.

Because the WebSphere Load Balancer does not support a HiperSockets connected network, we bypassed the WebSphere Load Balancer for these measurements. The Proxy and ReversePass statements in the ibmproxy.conf file were changed, as shown below, to point to the web server.

Proxy /* http://192.168.30.100/* :80

ReversePass http://192.168.30.100/* http://192.168.40.90