|
|
Distributing TCP/IP workload among systems within a Parallel Sysplex can be achieved through the Sysplex Distributor, which is built on Dynamic virtual IP addresses (DVIPA). Dynamic virtual IP addressing (DVIPA) is a z/OS Communication Server function that is used in high availability configuration in sysplex.
The Virtual IP Address, or VIPA, provides an IP address that is owned by a TCP/IP stack but that is not associated with any particular physical adapter. Because the VIPA is associated with a virtual device, it is always available as long as its owning TCP/IP stack is functional. For systems such as zSeries with multiple network adapters, VIPA provides failure independence from any particular adapter or link, as long as at least one is available and connected. VIPA becomes unavailable when its owning TCP/IP fails.
DVIPA improves the VIPA function by allowing a TCP/IP stack to be moved from one system to another in the sysplex. DVIPA takeover is possible when a DVIPA is configured as active on one stack and as backup on another stack within the sysplex. When the stack on which the DVIPA is active terminates, then the backup stack will automatically activate the DVIPA and notify the routing daemon. For DVIPA takeover to be useful, the applications that service the DVIPA addresses must be available on the backup stacks.
DVIPA can be used by the Deployment Manager and by appservers.
