Dbvisit Standby must be scheduled on both the primary (all primary RAC nodes) and standby servers.
It is possible to schedule Dbvisit only on the primary server using the INITIATE_DBVISIT_ON_STANDBY variable. Ensure you understand the implication before using this feature. See variable INITIATE_DBVISIT_ON_STANDBY in the Dbvisit Standby configuration variables (DDC) section for more details.
Preferred scheduling method
Dbvisit Standby can be scheduled using Dbvserver (see Scheduling Dbvisit Standby with Dbvserver scheduler - all platforms).
If Dbvisit Standby is scheduled in Dbvserver then no other scheduling software is required.
A decision must on the maximum time that the standby database may be behind the primary database. This is a business decision, but certain factors play a key role. These are:
- Speed of the network
- Activity on the database
- Speed of the disks
- Compression method chosen and CPU power to compress and uncompress archive log files.
A good recommended time frame is to schedule Dbvisit Standby every 10 minutes on both the primary and standby servers.
Using CRON to schedule Dbvisit Standby
If Dbvserver is not running, then Dbvisit Standby can be scheduled in cron or other scheduling software.
To schedule Dbvisit Standby, add a cron entry to the Oracle software owner on both the primary and standby server. This entry will run 24x7 and every 10 minutes. It is recommended that the standby cron is scheduled a little later than the primary cron. This ensures there are log files to be applied when Dbvisit Standby executes on the standby server.
To edit the cron type in crontab -e
Dbvisit Standby needs to be scheduled separately on each primary node in the Oracle RAC. It is recommended that Dbvisit Standby is scheduled at different times on each node. For example:
node1 – Schedule every hour at 00, 15, 30, 45
node2 – Schedule every hour at 05, 20, 35, 50