The initialization of the split mirror as snapshot performs a crash recovery, rolls back all uncommitted transactions, and makes the database available for any read or write operation.

DB2 HADR (High availability Disaster Recovery) configurations can provide both resiliency of availability and some load balancing through use of the secondary mode as a read-only database.

Most optimizations, checkpoint processing (aggregating intermediate results so that recovery actions never need to read the entire log), and "fringe cases" are beyond our scope.