The production journal holds redo log buffers until the logs are transferred to the recovery server. Then the logs are available to receive new application write data. Sizing the journal properly prevents the recovery server from falling so far behind the production server that dynamic recovery must occur for the recovery server to catch up. If the journal is too small, then transfers between the production server and the recovery server are performed more frequently than is efficient. If the journal is too big, then the recovery server may fall so far behind the production server that dynamic recovery must occur.
The appropriate size of the production journal is proportional to the length of network or recovery server downtime that Assure MIMIX for AIX can sustain without falling into dynamic recovery, or the amount of data in write throughput spikes that exceed system bandwidth that Assure MIMIX for AIX can sustain without falling into dynamic recovery.