Changing HADR synchronization modes

Synchronization modes determine how primary logs are propagated and synchronized with the standby database when the systems are in peer state. The stricter the synchronization mode, the more influenced the performance on the primary database. There are three synchronization modes: SYNC, NEARSYNC, and ASYNC.

Getting ready

In this recipe, we will switch first to NEARSYNC mode, then to SYNC synchronization mode, and then back to ASYNC mode.

The HADR_SYNCMODE parameter mentioned previously controls the synchronization mode of HADR. Since this parameter is not dynamic after any modification, a HADR and database restart is needed.

How to do it...

The parameter HADR_SYNCMODE is not dynamic, so every change to the synchronization mode requires a database restart for both the primary database and standby database.

Changing to NEARSYNC synchronization mode

1. Change the value of HADR_SYNCMODE, on both the databases, to NEARSYNC synchronization mode:

   [db2inst1@nodedb22 ~]...