XRF and VTAM generic resources
Extended Recovery Facility (XRF) systems help ensure session persistence and the availability of IMS resources. There are two types of XRF systems: XRF systems that use VTAM® multinode persistent sessions (MNPS) and XRF systems that use a USERVAR. XRF with MNPS systems can participate in a VTAM generic resource group, but XRF with USERVAR systems cannot.
XRF with MNPS and VTAM generic resources
For XRF with MNPS systems in a generic resource group, VTAM associates the generic resource name with the MNPS name of the XRF with MNPS systems instead of the APPLID name. Terminals that want to log on directly to an IMS that is part of an XRF with MNPS system must use the MNPS name.
Including an XRF with MNPS system in a generic resource group does not guarantee session persistence for terminals logging on using the generic resource name unless every IMS in the generic resource group is also part of an XRF with MNPS system.
If you use XRF with MNPS and are migrating off of the 3745 controller, be aware that you might encounter some performance limitations.
- Use the Communication Controller for Linux® on System z® (CCL) as a replacement for the 3745 controller, which allows continued use of XRF.
- Migrate from XRF to VTAM Generic Resources (VGR), which requires a parallel sysplex environment.
XRF with USERVAR and VTAM generic resources
Although XRF systems with USERVAR cannot participate in a generic resource group, they can coexist in the same sysplex as a generic resource group. In this case, generic resource names and USERVARs must be different.
XRF with USERVAR systems can participate in a shared-queues environment.