Dual Mode Replication
Publication Date: 2015-Nov-20
The IP.com Prior Art Database
Disclosed is a single replication product capable of operating with concurrent use of both the disconnected and connected models.
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Dual Mode Replication
Developers build replication products around one model of operation, either a connected or a disconnected model, which only
works within that single model of operation. The advantage of a disconnected model is the independent operation of multiple agents. An agent need not wait for successful propagation of the data to continue processing ; however, measures must be taken to guarantee delivery of this data to the target system, which increases overhead costs on the source system. The advantage of the connected model is lower overhead costs because the data does not have to be persisted until it reaches its final destination .
Clients can achieve both types of replication by installing and maintaining two separate products. This carries higher costs than maintaining a single product does, particularly on the mainframe where duplication of work leads to much higher operating costs.
The novel contribution is a single replication product capable of operating with concurrent use of both the disconnected and connected models.
A disconnected and asynchronous model pushes data to a target system; it does not need to communicate with the target agent.
A connected model opens a connection to the target system and directly communicates with the target agent . Both models have relevance in the replication world; therefore, it is necessary for an agent to simultaneously use both models in order to operate with agents using either model. This raises problems, such as the determination of a suitable restart point in the log when simultaneously operating using both models.
In the disconnected mode, the data is persisted using the transport method (a queue) and the source agent fully controls the restart position. In the connected mode, the transport method guarantees the delivery of data to the target agent, but data is not persisted until it is applied to the target system. In-flight data may be lost when replication is stopped, so only the target agent can control the point of restart. As part of this solution, an agent operating with the disconnected model is enhanced to also operate in a connected model in a transparent way. Data stored locally (disconnected model) and remotely (connected model) must be considered when determining the point of re...