Coupling facility structure failures
When a coupling facility structure fails in a IMS batch environment, all batch jobs terminate. In a DB/DC or DBCTL environment, all IMS systems in the data-sharing group temporarily suspend data sharing.
When a structure fails, what happens depends on the operating environment:
- Batch environment
- All IMS batch jobs that were connected to the coupling facility terminate with a U3303 abend.
- DB/DC or DBCTL environment
- All IMS systems in the data-sharing group temporarily suspend data sharing. If the structure that failed was an OSAM or VSAM structure, IMS tries to rebuild the structure. If the rebuild is successful, all IMS systems connect to the new structure and data sharing continues. If the structure that failed was an IRLM structure, all IRLMs try to rebuild the IRLM structure. If the rebuild is successful, all IRLMs connect to the new structure and locking for data sharing continues.
Example: Figure 1 shows the configuration for an OSAM structure failure. When the OSAM structure on coupling facility CF02 fails, the following happens:
- All IMS systems suspend data
sharing. If you display the status of the structure at this point
(using the DISPLAY XCF,STRUCTURE,STRNAME=OSAMSESXI command),
output shows that the structure is in the quiesce phase of rebuild,
as shown in the following example.
08:50:59.29 D XCF,STRUCTURE,STRNAME=OSAMSESXI 08:51:13.32 IXC360I 08.50.59 DISPLAY XCF 143 STRNAME: OSAMSESXI STATUS: REASON SPECIFIED WITH REBUILD START: STRUCTURE FAILURE REBUILD PHASE: QUIESCE POLICY SIZE : 2048 K PREFERENCE LIST: CF02 CF01 EXCLUSION LIST IS EMPTY ⋮ * ASTERISK DENOTES CONNECTOR WITH OUTSTANDING REBUILD RESPONSE CONNECTION NAME ID VERSION SYSNAME JOBNAME ASID STATE ---------------- -- -------- -------- -------- ---- ------- *IMS1 03 00030015 MVS1 DLIOCSA8 003A ACTIVE *IMS2 01 00010026 MVS2 DLIOCSB8 0038 ACTIVE *IMS3 02 0002001D MVS3 DLIOCSC8 0038 ACTIVE - When all IMS systems suspend
data sharing, a new structure is built. All IMS systems are then connected to the new structure
and data sharing resumes. If you display the status of the new structure
after rebuilding, output is similar to that shown in the following
example.
08:52:39.78 D XCF,STRUCTURE,STRNAME=OSAMSESXI 08:52:40.43 IXC360I 08.52.39 DISPLAY XCF 168 STRNAME: OSAMSESXI STATUS: ALLOCATED POLICY SIZE : 2048 K PREFERENCE LIST: CF02 CF01 EXCLUSION LIST IS EMPTY ACTIVE STRUCTURE ---------------- ALLOCATION TIME: 03/25/94 08:51:27 CFNAME : CF01 COUPLING FACILITY: ND01... PARTITION: 0 CPCID: 00 ACTUAL SIZE : 2048 K ⋮ CONNECTION NAME ID VERSION SYSNAME JOBNAME ASID STATE ---------------- -- -------- -------- -------- ------------ IMS1 03 00030015 MVS1 DLIOCSA8 003A ACTIVE IMS2 01 00010026 MVS2 DLIOCSB8 0038 ACTIVE IMS3 02 0002001D MVS3 DLIOCSC8 0038 ACTIVE