Architecture Overview

The following diagram is a high level overview of the Dbvisit Standby Architecture.

From the diagram above we can summarize the core functionality of Dbvisit Standby as a 3 step process:

Log Extraction
Dbvisit Standby will extract the primary database archive logs from the database archive destination.
The following steps form part of the log extraction process:
  - The latest archive logs will be extracted to be shipped to the standby
  - A "logswitch" will be forced if no new logs were generated since last run
  - Logs will be compressed if compression option is selected
  - If configured, Dbvisit Standby can also manage the archive logs on the primary server; example purge logs older than specified time

Transport
The second step in the process will be to copy these extracted archive logs to the standby site.  
This transfer process is initiated from the primary server and the transfer process is secure. 
The following steps form part of the log transfer process:
  - The latest archive logs will be transferred using the Dbvisit Network (Dbvnet) or SSH (Unix Only)
  - The connection between the primary and standby site is encrypted and secure by default
  - Archive logs will be transferred in compressed format if required

  - From version 7, Archive logs are renamed to a standard format as part of the transfer process and will be stored on the standby server in new naming convention (example thread#_sequence#_resetlogs_id.arc)
  - Checksum values are generated to ensure logs are transferred successfully
  - Dbvnet is making use of of port 7890 by default and this port should be open for communication

Log Apply
The third step in the process is where Dbvisit Standby apply the transferred archive logs to the standby database.
The following steps form part of the log apply process:
  - On the Standby Server, Dbvisit Standby will pickup the transferred archive logs and apply them to the standby database
  - If configured, Dbvisit Standby can also manage the archive logs on the standby server; example purge logs older than specified time

The above is only a summary of the core functionality of Dbvisit Standby which is to extract, send and apply logs.