This document answers the question, "Can an Historical Data Server (HDS) be Pointed to Different Sides of a Cisco Intelligent Contact Management (ICM) Central Controller at Will?"
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Readers of this document should be knowledgeable of the following:
The information in this document is based on the software and hardware versions below.
The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are working in a live network, ensure that you understand the potential impact of any command before using it.
Before ICM Version 4.6.2 without SR 1 and Earlier
It is not possible for an Historical Data Server (HDS) to be pointed to different sides of an ICM Central Controller at will. Once an HDS is installed and it points to one side of the ICM Central Controller, you run the ICM setup later and point the HDS to the other side of the ICM Central Controller. If an HDS is re-pointed to the other side of the ICM Central Controller after being installed, you lose all historical data previously written to the HDS database.
The historical data is replicated on an HDS through a client/server. A Replication Server process runs on an ICM Logger when you run the ICM setup while the Logger installation is run. A peer Replication Client process runs on an HDS. Upon the initial installation of an HDS and when it points to a specific side of the ICM Central Controller, the Replication Server on the ICM Logger and the Replication Client on the HDS establish a start point for all HDS table data.
Once the initial synchronization is established between the replication client and server databases, data is replicated to each database table on the HDS from the Logger based on specific recovery key values. Once this intimate recovery key synchronization is established between an ICM Logger and an HDS, only these two systems can know and understand the recovery key sequence numbers.
If an HDS that is originally pointed to one side of the ICM Central Controller is then pointed to the other side, the recovery key sequence is broken. From that point on, the HDS does not replicate correctly, and the HDS database needs to be rebuilt from the beginning.
ICM Version 4.6.2 with SR 1 and Later
It is a supported feature to point the HDS from one side of the ICM Central Controller to the other. Complete the step-by-step procedure:
Shutdown all ICM processes on the HDS.
As a precaution, backup the HDS database by using Enterprise Manager Backup/Restore function.
Run the Truncate Table Recovery query to truncate (empty) the Recovery table in the HDS database by using Enterprise Manager SQL Query Analyzer
Run ICM setup on the HDS and switch the preferred side.
Start all ICM services on the HDS and the empty Recovery table to rebuild the HDS database from the Recovery table in the Logger database that the HDS is now pointing at.