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Redundancy is an optional EnterpriseSMS System 10 configuration. Redundant host computers, located at the same or different
geographical locations, can provide real time backup for one another.
REDUNDANT ENTITIES
Redundant entities are two or more servers on which identical synchronized databases or application software modules are
maintained. These servers may be connected over any Local or Wide Area Network. If a server containing a critical table
experiences a prolonged failure, replicates of the table on another server can still be accessed. When the primary server comes back
online, the database tables are resynchronized, regardless of the duration of the failure. Application programs then synchronize their
working, local databases on a peer to peer basis. As this is a transaction-oriented synchronization strategy, transactions are never lost.
RESYNCHRONIZATION
The Oracle database engine manages data resynchronization, while the EnterpriseSMS software manages application synchronization.
The fail-over/resynchronization processes between servers take place over either corporate or dedicated LANs or WANs. Therefore,
servers in the redundant entity can be located anywhere in the world.
HIGH LEVEL OF DATA INTEGRITY
Redundant network access can be implemented by duplicating the network cards in each server. In this case, each server has two
paths to the network, two paths to each computer, and two paths to each of the other servers. Therefore, a failure in any of these
components or pathways does not interrupt processing. This capability provides a high level of data and application integrity, as well as increasing system uptime.
If the primary server should experience downtime, the other server picks up the operation of the system, a transition that is seamless
to the user outside of the re-login process. When the primary server comes back online, the databases synchronize and the
primary takes up the processing load again, a transition unnoticed by the system users, except for the need to re-login.
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