Release 10.1B: OpenEdge Replication
User Guide
Using the deferred agent startup implementation
By using the deferred agent startup implementation, you can configure OpenEdge Replication to allow database activity sooner than if you use the default implementation. The deferred agent startup mode allows you to create a target database by doing an online backup of the source database. In contrast, the default implementation requires that the source database be shut down while you perform the backup.
To use deferred agent startup, you must specify the
defer-agent-startup
property for the OpenEdge Replication server in the[server]
section of the property file. If you setdefer-agent-startup
to a valid, non-zero time-out value, the source database can be active before the OpenEdge Replication server even contacts its configured agent(s). For more information on this property and its values, see the "OpenEdge Replication property files" section and the "Server properties" section.The deferred agent startup implementation configures the OpenEdge Replication server to do the following:
- If the OpenEdge Replication server cannot connect to its configured agent(s) on the first connection attempt, it will go into deferred agent startup mode.
- While in deferred agent startup mode, the OpenEdge Replication server will wait five minutes and then attempt agent connection again.
Note: If you do not want to wait the five minutes for the server to attempt connection to the agents, you can force agent connection using the- The OpenEdge Replication server will attempt to connect every five minutes until all agent(s) are connected, or until the time-out specified in the
defer-agent-startup
expires.connectagent
command of the DSRUTIL utility. For more information, see the "DSRUTIL utility" section.
To canceldefer-agent-startup
, use thecancelDefer
command of the DSRUTIL utility.- Once the server connects to the agent(s), then startup, initialization, and synchronization are performed.
- During the entire connection process, source database activity continues to occur but will be halted briefly while the OpenEdge Replication server reinserts itself into normal RDBMS AI block processing.
Following is an overview of the tasks you must perform to create the deferred agent startup implementation of OpenEdge Replication.
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To use the deferred agent startup implementation:
- Execute your
PROENV
script every time you open a command-line window or shell, and ensure that you have$DLC
,$PROMSGS
,$DSRHOME
, and$PROCFG
environment variables set correctly.- Shut down the source database.
- On the source machine, do the following:
Note: Step a is not necessary if you prefer to do an online backup of the source database. Online backup is preferable in situations where the database is large, backups are time consuming, and you want to minimize the downtime of the database. For more information, see the "Setting up the source database (online backup)" section.- Create an initial backup of your source database.
- Create a structure file (
.st
) of the source database.- Ensure after-imaging is set up and running.
- Enable the source database for OpenEdge Replication.
Note: Step e is not necessary if you intend to create an online backup. See the "Setting up the source database (online backup)" section.- Perform an incremental backup of the source database.
- Configure your OpenEdge Replication server by doing the following:
- Configure the OpenEdge Replication server properties file to set the
defer-agent-startup
property to a valid time-out value.- Configure the OpenEdge Replication server properties file for your other server properties.
For more information, see the "Configuring the OpenEdge Replication property files" section and the "OpenEdge Replication properties" section.
- Start the source database.
- If you have not already created an offline backup, create an online backup of the source database.
- On the target machine do the following:
- Use the source database backup as an initial copy of the target database.
- Enable the target database for OpenEdge Replication.
For more information about these tasks, see the "Setting up the target database" section.
- Configure the OpenEdge Replication agent properties file.
- Start the OpenEdge Replication target database.
- Wait for the OpenEdge Replication server to connect to the agent(s), or use
DSRUTIL connectagent
for force a connection without waiting. For more information onconnectagent
, see Table 5–4.Once the synchronization between the OpenEdge Replication server and agent(s) is complete, normal OpenEdge Replication target database activity is allowed.
Special considerations for deferred agent startup
Schema updates are not allowed while the OpenEdge Replication server is performing synchronization. If schema updates are being performed when failure recovery synchronization begins, source database updates will block until failure recovery is complete.
Source database activity cannot continue without the agent(s) connected when synchronous replication is being used.
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