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User Guide
Moving From Failure to Recovery with OpenEdge Replication : Transition : Planning for transition
 

Planning for transition

To use transition effectively, you must set all the transition properties. If you do not set the transition properties, full transition processing does not occur. Instead, the extent of transition is limited to changing the role of a database from target to normal.
Plan for transition by making all of the following decisions:
*Which is the primary and which is the secondary database?
To begin transition planning, decide which database is your primary database and which is your secondary database. The primary database is the one on which users initially perform updates.
In the Transition properties, modify the responsibility property (which is currently used for information purposed only) to identify the type of database. The possible values are primary and secondary.
*What type of transition will occur?
Consider whether the target database will be transitioned to a source database or normal database.
In the Transition properties, set the database-role property to identify the new role of the database once it is transitioned. Possible values are reverse and normal. If you choose reverse, the role of the database is reversed such that a source database becomes a target database and a target database becomes a source database. If you choose normal, which is the default value, the role of the database becomes that of a normal database, meaning that it is no longer enabled for replication.
*What type of after-imaging functionality should be implemented?
You can choose to start AI automatically on the transitioned database. You can also add AI areas.
In the Transition properties, modify the after-imaging properties auto-begin-ai, auto-add-ai-areas, and ai-structure-file to set AI behavior, as follows:
*You can set the auto-begin-ai property value to 0 if you do not want AI to begin automatically after a target-to-source transition. To begin AI automatically after a target-to-source transition, set the value to 1.
*You can set the auto-add-ai-areas property to 0 if you do not want to add AI areas to the database automatically (when a database is transitioned to a source database or there are currently no AI areas for the database). To add areas to the database automatically by using the structure file specified in the ai-structure-file property (when a database is transitioned to a source database or there are currently no AI areas for the database), set the value to 1.
*You can set the name of the structure file (which contains the list of AI areas to add) in the ai-structure-file property.
*What types of backup do you want to perform during transition?
Consider what can you accomplish with each backup method, and why it might be advantageous to use one method instead of another method.
In the Transition properties, modify the backup properties backup-method, backup-arguments, and incremental-backup-arguments to set the type of backup you want to perform during transition and before AI is enabled, as follows:
*You can set the backup-method property to mark to identify the database as backed up; marking the database as backed up does not allow future AI extents to be used when recovering from a disaster.
To back up the database offline by using the OpenEdge PROBKUP utility, set the property to full-offline. The backup is performed in two steps. The first backup is a full backup, which is performed before AI is enabled for the database. The second backup is an incremental backup, which is performed after AI is enabled and after the role of the database is changed.
To back up the database online after the database is restarted, which occurs after the database has been transitioned, set the property to full-online.
*You can set the backup-arguments property for the arguments required for the full online and offline backups performed for the database.
Keep in mind that you must specify, at a minimum, the target file or device in these arguments for both online and offline backups. To avoid overwriting a backup, do not use the same target file or device for both the backup and the incremental backup. Begin the arguments with device-name, and do not use backup validation parameters (such as -vp and -vf).
*You can set the incremental-backup-arguments property for the arguments required for the offline incremental backup performed after AI is enabled and the database's role is reversed. Begin the arguments with device-name.
*Do you want the database to restart automatically after transition?
Think about whether you want to control database startup or have the transition process start the database.
*In the Transition properties, modify the following automatic transition properties to specify whether the database should be automatically restarted after transition:
*restart-after-transition
*start-secondary-broker
*source-startup-arguments, target-startup-arguments, or normal-startup-arguments
*source-secondary-broker-startup-arguments, target-secondary-broker-startup-arguments, or normal-secondary-broker-startup-arguments
You can set the restart-after-transition property to 0 if you do not want to restart the database automatically after transition is performed. Set the property to 1 to restart the database automatically after transition is performed. When you specify this value, you must also supply the *-startup-arguments properties, or the database startup will fail.
Set the start-secondary-broker property to 1 to start a secondary broker after transition is performed.
*Set the *-startup-arguments property or properties as follows:
If the database is transitioned to a normal database, specify the normal-startup-arguments property. These arguments are used when the database is started. The arguments will be appended to the PROSERVE command. In most cases, the only argument specified here should be -pf followed by a parameter file name, as shown here:
-pf db-name.normal.pf
If the database is transitioned to a source database, you must specify the source-startup-arguments property. The arguments are appended to the PROSERVE command and are used when the database is started. In most cases, the only argument specified should be -pf followed by a parameter file name, as shown here:
-pf db-name.source.pf
Because the database is a source, you must also specify the following argument, which is case-sensitive, as an indication to the broker to start the Replication server:
-DBService replserv
If the database is transitioned to a target database, you must specify the target-startup-arguments property.The arguments are appended to the PROSERVE command and are used when the database is started. In most cases, the only argument specified here should be -pf followed by a parameter file name, as shown here:
-pf db-name.target.pf
Because the database is a target, you must also specify the following arguments (note that -DBService is case-sensitive) as an indication to the broker to start the Replication agent and listen on the TCP/IP port as specified:
-DBService replagent -S
{ port-number | service-name }
If the database role is reversed, you must specify the source-startup-arguments property and the target-startup-arguments property.
For additional details about the source-, target-, or normal-startup-arguments, see Sample of a startup parameter file used by transition .
*Will transition automatically attempt to recover in the event of a failure?
A backup must exist in order for automatic recovery to occur.
In the Transition properties, modify the recovery-backup-arguments property, which determines whether transition automatically attempts a recovery. Specify the device name, followed by any other backup arguments.
Once you make each of these decisions, you can set the transition properties accordingly, as described in Setting transition properties . (See Transition properties summary for a complete list of all transition properties.)