Neuron is designed to run in environments as small as a single developer machine and as large as a major enterprise.
In a single-server configuration, one ESB server provides the infrastructure for the ESB. Should the ESB server be taken offline, the quality of service provided by the transport will determine whether communication is still possible.
The use of a database is optional in a single-server deployment. A database will only be required if you want to enable message auditing and reporting.
Server Outage Consequences in a Single-Server Configuration
The degree of disruption to existing programs when a server outage occurs is a function of channel type as shown below. In general, new connections to the bus are not possible when the ESB server is down; however, existing clients may continue to function. Clients should resume connectivity when the ESB server is back online.
Server Farm Deployment
In a server farm configuration, multiple ESB servers provide the infrastructure for the ESB. Use of a server farm should be considered when high availability or high capacity is needed.
A hardware or software load balancer is required in order to take full advantage of server farm mode.
The use of a database is required in a server farm deployment.
Server Outage Consequences in a Server Farm Configuration
In a server farm configuration, multiple ESB servers provide the infrastructure for the ESB. Should an individual ESB server go down, other servers keep the infrastructure going and disruption to programs is avoided or minimized. Use of a server farm should be considered when high availability or high capacity is needed for the publishing system itself. If the Neuron server does not maintain state then multiple Neuron servers running the same esb configuration may be configured behind a load balancer to provide HA much like you would provide redundancy with traditional web server or application servers.
An ESB server outage in a server farm configuration (where at least one other server continues to run) is minimally disruptive to applications connected to the bus. In general, operations continue unchanged when a server goes down. There may be some degree of disruption to existing programs when a server outage occurs depending on the channel type in use as shown below. In addition, if the primary server goes out of server certain primary-only functions such as bridges will stop
|Peer||Messaging continues uninterrupted.|
|MSMQ||Messaging continues uninterrupted.|
|RabbitMQ||Messaging continues uninterrupted.|
|TCP/IP||Messaging continues uninterrupted. Messages buffered on the server will be lost.|
|Named Pipe||Messaging continues uninterrupted. Messages buffered on the server will be lost.|