Handling New Connections During a User-Managed Rebuild Process

How new connections are handled differs substantially between rebuild and duplexing rebuild.

Rebuild
The system permits new connections to the original structure up until all responses for the Rebuild Quiesce event have been received. (The system must receive IXLEERSP responses from all connected users that are participating in rebuilding before it reports a Rebuild Connect event.)
The system informs the new connection that rebuild is in progress by returning reason code IXLRSNCODESPECIALCONN from the IXLCONN invocation. The new connector can find information about the rebuild in the IXLCONN answer area. CONAREBUILDINFO contains information about the reason for the rebuild, failed-persistent connectors, the percent loss of connectivity associated with an MVS-initiated loss of connectivity rebuild, and flags to indicate whether rebuild is in progress (CONAREBUILD) or rebuild stop is in progress (CONAREBUILDSTOP).
- If rebuild is in progress, the new connection can participate by first stopping activity to the original structure and then providing an IXLEERSP response with EVENT=REBLDQUIESCE. XES will monitor this required response.
- If rebuild stop is in progress, the new connection must provide an IXLEERSP response with EVENT=REBLDSTOP. XES will monitor this required response. See Stopping a User-Managed Rebuild Process.
Connections can listen for ENF event code 35 to determine when rebuilding is complete.

Note that for structure rebuild, a new connector can connect to the structure only up until the Rebuild Quiesce sync point is reached.
Duplexing Rebuild
New connectors to the old structure when the structure is in the Rebuild Quiesce, Rebuild Connect, or Duplex Established phases, are allowed with the following qualifications:
- Rebuild Quiesce Phase
  A new connector to the old structure who requests to connect to a structure during the Rebuild Quiesce phase receives a valid CONTOKEN from IXLCONN for accessing the old structure. The connector's event exit does not receive a Rebuild Quiesce event, but the connector should examine the connect answer area to determine the state of the rebuild (such as CONAREBLDFLAGS to determine whether duplexing is in progress and CONAREBLDPHASE to determine the phase in which the connect occurred). The connector is expected to provide an IXLEERSP EVENT=REBLDQUIESCE confirmation, at which time the original CONTOKEN is invalidated. XES will monitor the required response to this event.
- Rebuild Connect Phase
  A new connector to the old structure who requests to connect to a structure during the Rebuild Connect phase receives a CONTOKEN from IXLCONN that is not valid yet for accessing the old structure. The connector's event exit does not receive a Rebuild Quiesce event, and the connector is neither expected to return an IXLEERSP EVENT=REBLDQUIESCE confirmation, nor will it receive a Rebuild Connect event. However, the connector is expected to issue an IXLCONN REBUILD to connect to the new structure, at which time the original CONTOKEN will be validated and a new CONTOKEN will be returned from IXLCONN REBUILD. From that point on, the new connector is expected to participate in the duplexing process by propagating data to the new structure and comfirming its completion with IXLREBLD REQUEST=COMPLETE. XES will monitor the required responses to these events.
- Duplex Established Phase
  A new connector to the old structure who requests to connect to a structure during the Duplex Established phase receives a valid CONTOKEN from IXLCONN for accessing the old structure. The connector's event exit does not receive a Rebuild Quiesce event, and the connector is neither expected to return an IXLEERSP EVENT=REBLDQUIESCE confirmation nor will it receive a Rebuild Connect event. However, the connector is expected to issue an IXLCONN REBUILD that will return a valid CONTOKEN with which to access the new structure. XES will monitor for the required IXLCONN REBUILD invocation. From that point on, the new connector is expected to participate in the duplexing rebuild process as are the other connectors.
  
  If a switch to the new structure is in progress when the connection completes (CONAREBUILDSWITCHINPROGRESS indicator), the connector is expected to participate in the switch by first issuing IXLCONN REBUILD to connect to the new structure and then IXLREBLD REQUEST=DUPLEXCOMPLETE when appropriate. XES will monitor the required responses to this event.