Enabling or Disabling Full Sync Replication

When activated the full sync option for system replication ensures that a log buffer is shipped to the secondary system before a commit takes place on the local primary system.

Prerequisites

You have permission Service(ForcedPrepare,ForcedUnPrepare,ForcedStart,ForcedStop).

For more information, see Standard Permissions.

Context

The full sync option can be enabled for sync replication (that is not for syncmem). With the activated full sync option, transaction processing on the primary blocks, when the secondary is currently not connected and newly created log buffers cannot be shipped to the secondary site. This behavior ensures that no transaction can be locally committed without shipping the log buffers to the secondary site.

The setting of parameter enable_full_sync in the system_replication section of the global.ini file can have the following values:

DISABLED

Full sync is not configured at all. The parameter enable_full_sync = false in the system_replication section of the global.ini file.
ENABLED

Full sync is configured, but it is not yet active, so transactions do not block in this state. To become active the secondary has to connect and REPLICATION_STATUS has to be ACTIVE.
ACTIVE

Full sync mode is configured and active. If the network connection to a connected secondary is closed, transactions on the primary side will block in this state.

Procedure

Choose Operations.
Choose Systems from the tabs.
From Operations dropdown for the primary system, choose SAP HANA Replication Enable / Disable Fullsync System Replication.
Set the parameter Fullsync as required:
- To enable full sync on the primary, choose enable.
- To disable full sync on the primary, choose disable.
Optional: Select the Set Note checkbox and enter a note to be displayed in the Description column of the instance.
Choose Execute.
It changes the setting of the parameter enable_full_sync in the system_replication section of the global.ini file accordingly. In a running system, full sync does not become active immediately. This is done to prevent the system from blocking transactions immediately when setting the parameter to true. Instead, full sync has to first be enabled by the administrator. In a second step it is internally activated, when the secondary is connected and becomes ACTIVE. If full sync is enabled when an active secondary is currently connected, the FULL_SYNC will be immediately set to ACTIVE.