FMS Replication and Data Synchronization

FMS can currently be configured for FMS data synchronization/replication, or to support FMS redundancy in the event of a failover. Use of either feature is optional.

You must have the required security authorization to configure FMS data synchronization and replication or FMS redundancy. Your User ID must satisfy the user authentication requirements in your system (Microsoft Windows) to give you permission to write to the configuration files containing the required settings. See Security for more information about configuring security access.

FMS Redundancy

The FMS redundancy feature set can be configured for data-center redundancy, but not yet for local redundancy. Enabling the redundancy feature currently disables use of the data synchronization/replication feature, and FMS replication and data synchronization keywords must be disabled if they have been previously configured.

See CygNet Redundancy and Configuring FMS Redundancy for more information.

FMS Replication/Data Synchronization

The FMS data synchronization feature set is similar to the replication implementation for all DBS-based services, in that the data model is a pull from, not a push to, the Master service, and a number of Slave services can be configured to replicate from a single Master service. Enabling the replication feature disables use of the redundancy feature, and once configured, FMS replication and data synchronization keywords must be disabled before inclusion of an FMS in a redundant environment.

In CygNet Measurement, in addition to the disaster recovery service defined as a part of the replication process, business services can also be defined.

• Master service - A maximum of one FMS is set as the data source for replicated services, and is designated as the "Master" service for the data synchronization relationship.

• DR Slave service - A maximum of one FMS per Master can be set up as a disaster recovery service, and is designated as the "DR Slave" service in the relationship. It is replicated from the Master service. Once it is replicated as a DR Slave, its database will exactly match all the data in the Master service.

• Business Slave service - A maximum of three FMS services per Master can be set up for business purposes, and are designated as "Business Slave" services in the relationship. A Business Slave is also replicated from the Master service. Once it is replicated as a Business Slave, its database will be based on a subset of the data in the Master service, and will be essentially read-only; it cannot directly process data or execute FMS commands that modify the Master database, although it can execute FMS commands that normalize the data in or perform maintenance for its own database, export data, create reports, etc.

Replication Considerations

There are some considerations to take into account prior to setting up your FMS system replication.

• Database contents - A database in replication mode is assumed only to contain data from the Master service.
• Database names - Each database name must be unique within a domain.
• For systems using the FMS Internal Database, all database names for Master and Slave services must be unique.
• For systems using Microsoft SQL Server, database names for Master and Slave services on the same server must be unique, but database names for services residing on different servers can share the same name, if desired.

• Service Domain - All services in the relationship do not need to be on the same domain. When the services are on different domains, the domain must be included in the service name, e.g. type [Domain]Site.Service instead of Site.Service.
• Database Schema - All replicated services must have the same version of the database schema. If the database schema version of the Master service is older or newer than that of the Slave service, the replication will not begin. In such a case, both services would still run, but the replication would display a "configuration error" status.
• Data Retention Periods - Each service in the relationship must have a properly configured and coordinated DATA_RETENTION keyword in its configuration file. See Required Data Synchronization Keywords for more information.

Replication Modes and Data Sharing Roles

FMS Replication is an optional process and no replication is in place by default. Each FMS service's replication relationship is defined in its service configuration file (CygNet\Services\FMS\fms.cfg). Changes must be made before starting the service; they cannot be made at runtime.

Configuration file keywords required to define replication behavior can be set by authorized users. See FMS Configuration File Keywords in the Services section for more information about Data Synchronization keywords used to define replication and data sharing roles.

If you do not want to set up replication for an FMS service, leave the Data Synchronization Keywords section of the configuration file commented out, or define the value for the DS_MODE keyword (the data sharing mode) as NONE.

If you want to set up replication for your FMS services, define the value for the DS_MODE keyword as REPLICATION in the FMS configuration file (CygNet\Services\FMS\fms.cfg), and proceed to configure the service relationships for each involved service.

When in replication mode, FMS services can function in one of three possible data sharing roles.

• Master
• DR Slave
• Business Slave

FMS services involved in replication can be defined in their configuration files as a REPL_MASTER (Master) service, a REPL_SLAVE_DR (Disaster Recovery Slave) service, or a REPL_SLAVE_BUSINESS (Business Slave) service. These data sharing roles and their relationships are defined in the configuration files for each service involved in the replication relationship. Only one service can be defined as the Master service. Only one service can be defined as the DR Slave service, which maintains an exact copy of the Master database. Multiple services can be defined as Business Slave services, which maintain a mostly read-only copy of the Master database, in accordance with a specified data retention period (if used).

Replication Mode Functionality

Each replication mode (FULL/REPOSITORY) and service role (Master/Business Slave) supports applicable FMS commands. The following table lists available command functionality for each replication mode service role.

FMS Command Name	FULL Mode		REPOSITORY Mode
	Master Service	Business Slave Service	Master Service	Business Slave Service
Device Communication Commands
Request Current Configuration		N/A		N/A
Request Data		N/A		N/A
Request Missing Data		N/A		N/A
Request New Data		N/A		N/A
Request Product Data		N/A		N/A
Send Gas Quality		N/A		N/A
Flow-Cal Request Missing Data*	N/A	N/A		N/A
Flow-Cal Send Gas Quality*	N/A	N/A		N/A
Export Commands
Device Data CSV				N/A
Normalization View Data CSV			N/A	N/A
PPAs CSV		N/A	N/A	N/A
Flow-Cal Data CFX*
Flow-Cal Ticket Data TFX*
Flow-Cal Transaction Queue*		N/A		N/A
PGAS Data XML*
Import Commands
Configuration CSV		N/A		N/A
EmersonRoc Laptop		N/A		N/A
Events CSV		N/A		N/A
Gas Analysis CSV		N/A		N/A
Gas Quality CSV		N/A		N/A
History CSV		N/A		N/A
Totalflow laptop		N/A		N/A
Reports Commands
Balance Contribution
Balance Details
Balance Overview
Batch
Changed Device Data
Changed Station Data
Configuration
Device QTR
Device Total QTR
Event
Gas Analysis
Gas Device Raw QTR
Job***
Late Job***
Liquid Device QTR
Liquid Device Raw QTR
Missing Data
Missing Data Overview
Normalization View			N/A	N/A
Ticket
System Commands
Archive Data**		N/A		N/A
Detect New Devices		N/A		N/A
Estimate Station Data		N/A	N/A	N/A
Generate Smart Groups		N/A		N/A
Perform Database Maintenance
Precalculate Calibration Data***
Schedule Jobs***
Update Normalization Views			N/A	N/A
User Commands
Validate Data		N/A		N/A

* If installed; provided as an optional feature

** If enabled in the FMS configuration file (CygNet\Services\FMS\fms.cfg)

*** Available as a feature of CygNet Dispatch. Contact CygNet Sales for more information.

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More:

Configuring FMS Replication

Configuring FMS Redundancy