Replication is configured in the configuration file (CygNet\Services\FMS\fms.cfg) for each affected service. Depending on what role the service plays, different keywords will apply.
For each involved service, its replication behavior and relationship is defined by several keywords in the FMS configuration file.
In the Data Synchronization Keywords section of the configuration file, no replication is initially configured, and all data synchronization keywords in the configuration file are commented out. Uncomment only the applicable keywords necessary for each service, and enter appropriate values to define the replication relationships desired. See Data Synchronization Keywords in the FMS Configuration File Keywords topic for more information.
The following is an overview of the keywords that are appropriate for each replication service role you decide to set up.
| Data Synchronization Keyword | Master FMS Service | DR Slave FMS Service | Business Slave FMS Service |
|---|---|---|---|
|
Required |
Required |
Required |
|
|
Required |
Required |
Required |
|
|
N/A; leave commented |
Required |
Required |
|
|
Required in replication mode, when designating a DR Slave service N/A when designating Business Slave service(s); leave commented |
N/A; leave commented |
N/A; leave commented |
|
|
N/A; leave commented |
Required |
Required |
|
|
Required when in redundancy mode |
Required when in redundancy mode |
Required when in redundancy mode |
|
|
N/A; leave commented |
Optional |
Optional |
|
|
N/A; leave commented |
Optional |
Optional |
|
|
N/A; leave commented |
Optional |
Optional |
In the Database Info Keywords section of the configuration file, the DATA_RETENTION keyword must also be properly specified.
Example
If the Master service has a 180 day retention period, and the Business Slave service has a 5 year retention period, then only the most recent 180 days of data in the slave service can be validated.
See Database Info Keywords in the FMS Configuration File Keywords topic for more information.
The following is an overview of what the DATA_RETENTION keyword values mean for each replication service role you decide to set up.
| Data Synchronization Keyword | Master FMS Service | DR Slave FMS Service | Business Slave FMS Service |
|---|---|---|---|
|
Required Specifies the number of days of data to be retained in the database, when expired device data is purged during database maintenance. |
Required Specifies the number of days of data to be replicated from the Master service to the DR Slave service. Note: The value must equal the value set for the Master FMS Service. Also specifies the number of days of data to be retained in the database, when expired device data is purged during database maintenance. |
Required Specifies the number of days of data to be replicated from the Master service to the Business Slave service. Note: If the value is different from the value of the Master FMS Service, the system will use the smaller of the two values. Also specifies the number of days of data to be retained in the database, when expired device data is purged during database maintenance. |
You may optionally decide to copy the Master service database over to a Slave service prior to setting up replication, and then use the quick database comparison feature to save time.
Note: Use this keyword with caution, as it is possible to get a false positive on two databases that aren’t exactly the same.
Beginning replication from an existing FMS service could take a prohibitively long time, to run a line-by-line comparison against the potentially large size of an existing FMS database. If desired, to shorten the initial synchronization time for the replicated service, the database of the Master FMS service can be duplicated over to the replicated (Slave) site before starting the replicated service. You can then choose to enable the quick database comparison feature in the replicated service's configuration file, to allow the service to make a quick comparison and start the service.
To Enable Quick Database Comparison in a Replicated Slave Service
Once the replicated service starts, a quick validation check will be done to verify that the two databases (Master and Slave) are equal. This will prevent a full row by row comparison of the two databases, which may take a long time on a large database.
Replication must be enabled and defined in the configuration file for each service that is part of the FMS replication relationship.
To Enable Replication
Since you will need to accommodate time required for database backups or other functions (e.g. your FMS service is configured to do a majority of data polls at a particular part of the contract day), it may be helpful to black out replication during such periods to prevent a performance burden on the system. Replication blackouts can optionally be configured in the configuration file of any slave service.
To Black Out Replication
Example
If your contract hour is 9 a.m. and polling generally takes under five hours, you might want a DS_BLACKOUT_START value of 09:00 and a DS_BLACKOUT_END value of 14:00.
To monitor replication status in the FMS Console window, use the F4:Repl view. The console view displays the current status of the replication, the amount of data replicated, the estimated amount to replicate, and other helpful information. See CygNet Console for more information.
Most of the data on this view is also available via CygNet Explorer, using service info keywords available in the Service Details View, or through SVCMON points.