Persistence Service Transports

Each persistence service uses special-purpose transports of two kinds: client transports and cluster transports.

  • Client transports communicate between a persistence cluster and its client processes.
  • Cluster transports communicate within a persistence cluster.
Note:

Administrators usually use the default values for these transports.

However, when needed, you can configure the details of these transports as part of the persistence service definition (rather than as separate transport definitions). The remainder of this topic presents use cases for non-default values.

To set non-default values, see Persistence Service Definition Reference.

Mixed Environment

Environments that combine components from Release 6.x and Release 5.x, such as during migration to Release 6.x, could require non-default values carried over from Release 5.x.

Client Transport and Non-Blocking Send

Administrators can choose whether the client transport uses blocking or non-blocking send. This setting affects only the client end of the transport, as the persistence service end always uses non-blocking send.

This choice is relevant only when the publisher mode is Store - Send - No Confirm, because otherwise the application publishing rate is limited by confirmations from the persistence service. (See Publisher Mode.)

Furthermore, this choice has an effect on behavior only during peak message bursts, that is, if application publishing overwhelms the persistence service leader:

  • To favor maximum application publishing speed while accepting potential message loss in the store, choose non-blocking send.
  • To favor minimum message loss in the store while throttling application publishing speed, choose blocking send.

Disaster Recovery Transport

For background information, see Disaster Recovery.

For configuration, see Preparing FTL Servers for a Disaster Recovery Site, and Persistence Service Definition Reference.

Alternate Client Transport

Consider a heterogeneous environment in which the client host computers have different transport capabilities. For example, some hosts support RDMA transports, while others do not. For best performance, each client would use the fastest available transport protocol.

In such situations you can define a second client transport, called the alternate client transport, and assign clients on specific hosts to use that alternate transport. All other clients use the regular client transport.

To configure this transport, see Persistence Service Definition Reference.

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