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Glossary of Terms

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Certain terms are used during the installation process. This section lists the common terms used and their description.

Term Description
Primary Server The main host or server that runs the primary Oracle database. Dbvisit Standby will be installed on this server.
Standby Server / Secondary Server The remote, secondary or standby server, which runs the Oracle standby database. This can also be the reporting server that runs the reporting (standby) database. Dbvisit Standby will be installed on this server.

DBVISIT_BASE

(Dbvisit Standby Installation Directory)

The directory where Dbvisit Standby will be installed is known as the DBVISIT_BASE directory. It is recommended to keep this location the same on the primary and the standby servers.

The Default installation directory for Dbvisit Standby version 7 is

For Linux (UNIX Systems): /usr/dbvisit

For Windows Operating Systems: C:\Program Files\dbvisit

ORACLE_HOME The directory where the Oracle software also known as the Oracle executables, are installed. 
ORACLE_BASE This is where the administration files are kept for each database. This contains the diagnostic destination or admin directory containing the bdump, udump and cdump directories of each database.
The ORACLE_BASE is not strictly necessary to configure Dbvisit Standby. Dbvisit Standby uses the ORACLE_BASE to determine where some of the database files are located during the setup.  
Oracle software owner This is the Windows user or Unix account that owns the Oracle Software. In most cases this is the user "oracle". This should be the user used when installing Dbvisit Standby.
Archive log files Oracle Archive log files are "archived/backup" copies of the database Online Redo logs. Dbvisit Standby is using these files to recover and keep the standby database up to date.
Archive log gap The difference between the last archived sequence on the primary and the last applied sequence on the standby database. This figure should be near 0 (except when a delay is put in place on the standby using the APPLY_DELAY_LAG_MINUTES parameter in the Dbvisit Standby configuration file).
Transfer log gap The difference between the last archived sequence on the primary and the last archived sequence transferred to the standby server. The transfer log gap should be near 0.

log_archive_dest_n

(n can be 1-31)

Parameter in Oracle that determines where the Log files are kept on the server. This is also known as the Oracle Database Archive Log Destination.
The value of this parameter can be shown by the SQL command:
SQL>show parameter log_archive_dest
DDC DDC stands for:
Dbvisit Database Configuration and refers to the “DDC name”
DDC name Most Dbvisit Standby commands require the DDC name, or simply DDC. 
In most cases this is the same as the database name or ORACLE_SID. 
The DDC refers to the DDC file which is in the form: 
dbv_DDC.env 
This file contains the Dbvisit Standby settings for a particular primary and standby configuration. 
The DDC name and the ORACLE_SID can be different. 
The ORACLE_SID is a variable setting contained within the DDC file and is not linked to the DDC name. 
However in most cases the DDC and the ORACLE_SID are the same.
Example: If the database name (or ORACLE_SID) is orcl, then the DDC is orcl and the DDC file is dbv_orcl.env.
DDC file A Dbvisit Standby created text file which contains all the settings for each database. There will be a DDC file for each database or instance that has Dbvisit Standby configured. 
The DDC file contains all the necessary configuration information to keep the standby database up to date. The file(s) will be in the Dbvisit Standby Base (Install) directory and has the format: dbv_<DDC>.env

The default location for this file is: DBVISIT_BASE/standby/conf/

Example:

/usr/dbvisit/standby/conf/dbv_testdb.env

Where DDC is the name of the Dbvisit Database Configuration. In most cases this is the same as the database name. The DDC refers to the DDC file name which is in the form: dbv_DDC.env and contains the Dbvisit Standby settings for a particular primary and standby configuration.

From Dbvisit Standby version 8, when using Oracle RAC configurations, you will only need one DDC file and not 2 as in the past.

For multiple standby databases, each standby database must have a unique DDC file name.  
The DDC file can be manually edited and updated, this should only be done on the primary server. 
The updated DDC file will be automatically transferred to the standby server. Any manual changes to the DDC file on the standby server will be lost as the primary DDC file is seen is the master configuration file. 
From Dbvisit Standby version 8 there are no template fille called dbv_ORACLE_SID.env used.
Dbvisit Standby installation The installation of the Dbvisit Standby software. Also known as the DBVISIT_BASE directory.
Dbvisit Standby setup Configuration of Dbvisit Standby for a specific primary database so that Dbvisit Standby will keep the standby database up to date. 
Dbvisit Standby setup for a specific database will create the following:
1. A Dbvisit Standby Database Configuration (DDC) file
2.  Dbvisit Standby database repository (DDR) 
Dbvisit Standby setup is initiated with command:

cd DBVISIT_BASE/standby

dbvctl -o setup [–noprompt]


Dbvisit Standby database repository (DDR) As part of the Dbvisit Standby setup, Dbvisit Standby will a new SQLite repository database file in the DBVISIT_BASE/conf directory.
The Dbvisit Standby database repository is a small repository located outside the Oracle Database. The master copy of the repository is kept on the primary database server side and is only copied to the standby during initial creation and during Graceful Switchover.
Dbvisit Standby Archive log Management Module (AMM) Optional module that comes with Dbvisit Standby to manage the database archive logs.
Management and monitoring of the Oracle archive log space on either the primary, standby server or both.
The AMM is configured through command:
DBVISIT_BASE/standby/dbvctl -o setup [--noprompt]
The AMM settings are contained within the Dbvisit Standby Database Configuration (DDC) file.
Fail over In the event of a disaster, the standby database is activated to become the new primary database. The original primary database is no longer available.
To activate the standby database use the command:
./dbvctl -o activate -d <DDC>
Note: Activation cannot be reversed. A new standby database will have to be built.
Graceful Switchover Both the primary and standby database must be available. 
Reverses the roles between the primary and standby databases without data loss.
The primary database becomes the standby database and the standby database becomes the primary database.
Graceful Switchover is used to switch back to the original primary database after a disaster in which the standby database has been activated (failover).
Graceful Switchover may also be used for planned outages to perform an upgrade on the primary site by switching over the database users to the standby site as hardware or software is upgraded on the primary site. It may also be used to test the Disaster Recovery scenario. 
Role reversal See Graceful Switchover.
Switchover See Graceful Switchover.
Activation of standby database See failover. 
Transportable Media Transportable Media (TM) is an external device such as a USB drive that can be used to create the standby database. 
The TM is first plugged into the primary server and then manually transferred to the standby site and plugged into the standby server to complete the standby database creation process.
Using a TM is advantageous if the database is very large or the network is slow since the network is no longer used to transfer the copy of the database to create the standby database.
Dbvserver Dbvserver is the Web server that provides the web interface to Dbvisit. This component is optional and only required if:
·           Dbvisit Standby is configured and run through a web browser.
The default https port for Dbvserver is 8443.
One central configured Dbvserver can manage multiple standby database configurations
Dbvagent

Dbvisit Standby is must have the Dbvagent (agent) installed on each host that will be used in a Dbvisit Standby configuration.

The agent will be used by the central Web console as entry point into the server to execute Dbvisit Standby commands.

CLI - Command Line Interface  Dbvisit Standby can be configured and run through a command line interface (CLI) or a web-based interface (GUI). 
Throughout this user manual the CLI commands will be indicated with a icon
GUI - Graphical User Interface  Dbvisit Standby can be configured and run through a command line interface (CLI) or a web-based interface (GUI). 
Dbvserver is the web server that needs to be running for the web-based access to be available. 
Throughout this user manual the web-based or GUI options will be indicated with a  icon

 

Watch these explanatory videos for alternative overviews of our Dbvisit Standby Glossary of Terms: 

 

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