When the primary system splits a TrueCopy for Mainframe pair due to an error condition, the primary and secondary systems send sense information with unit check status to the appropriate hosts. This sense information is used during disaster recovery to determine the consistency of the S-VOL and must be transferred to the secondary site using the host failover software.
If the host system supports IBM® PPRC and receives PPRC-compatible sense information related to a TrueCopy for Mainframe pair, the host OS will perform the following actions:
- Temporarily split all application I/O operations to the P-VOL.
- Enter an IEA491E message in the system log (SYSLOG) that indicates the time that the P-VOL was split. Make sure that the system log is common to both the primary and secondary operating systems.
- Place specific information about the failure (SIM) in the SYS1.LOGREC dataset for use by service personnel.
- Wait for the IEA491E message to reach the secondary system.
- Resume all host application I/O operations to the P-VOL. If the P-VOL fence level setting does not allow subsequent updates, the primary system will return a unit check for all subsequent write I/O operations, and the application will terminate.
Make sure that the primary and secondary systems are configured to report the service level SIMs to the host. Use the raidcom modify remote_replica_opt command with the -service_sim option set to enable.