Within RFA, they include a very useful feature called "Warm Standby". This is highlighted within the "Features of RFA" section that I'm presently using that will automatically failover to a standby connection if my primary connection fails. Do I get something similar if I use EMA?
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No, EMA and the underlying UPA ValueAdd library do not support warm standby only cold standby.
For EMA here is a summary:
v3.0.1 - Fixes cold standby support.
v3.0.0 - No standby support at all.
Hot standby support is only implemented within TREP as part of the ADH server.
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@Ripley79, the connection failover is listed in the new features of EMA 3.0.1.
My configuration is as follows:
<ConsumerGroup>
<!-- DefaultConsumer parameter defines which consumer configuration is used by OmmConsumer -->
<!-- if application does not specify it through OmmConsumerConfig::consumerName() -->
<!-- first consumer on the ConsumerList is a default consumer if this parameter is not specified -->
<DefaultConsumer value="Consumer_3"/>
<ConsumerList>
<Consumer>
<Name value="Consumer_1"/>
<!-- Channel is optional: defaulted to "RSSL_SOCKET + localhost + 14002" -->
<Channel value="Channel_1"/>
<!-- Logger is optional: defaulted to "File + Success" -->
<Logger value="Logger_1"/>
<!-- Dictionary is optional: defaulted to "ChannelDictionary" -->
<Dictionary value="Dictionary_1"/>
</Consumer>
<Consumer>
<Name value="Consumer_2"/>
<!-- ChannelSet is optional: defaulted to "RSSL_SOCKET + localhost + 14002" -->
<ChannelSet value="Channel_1, Channel_2"/>
<Logger value="Logger_2"/>
<Dictionary value="Dictionary_2"/>
</Consumer>
<Consumer>
<Name value="Consumer_3"/>
<!-- ChannelSet is optional -->
<ChannelSet value="Channel_1, Channel_2"/>
<!-- Logger is optional: defaulted to "File + Success" -->
<Logger value="Logger_1"/>
<!-- Dictionary is optional: defaulted to "ChannelDictionary" -->
<Dictionary value="Dictionary_1"/>
</Consumer>
</ConsumerList>
</ConsumerGroup>
<ChannelGroup>
<ChannelList>
<Channel>
<Name value="Channel_1"/>
<!-- ChannelType possible values are: -->
<!-- ChannelType::RSSL_SOCKET - TCP IP connection type -->
<!-- ChannelType::RSSL_HTTP - Http tunnel connection type -->
<!-- ChannelType::RSSL_ENCRYPTED - Https tunnel connection type -->
<!-- ChannelType::RSSL_RELIABLE_MCAST - Reliable multicast connection type -->
<ChannelType value="ChannelType::RSSL_SOCKET"/>
<!-- CompressionType is optional: defaulted to None -->
<!-- possible values: None, ZLib, LZ4 -->
<CompressionType value="CompressionType::None"/>
<GuaranteedOutputBuffers value="5000"/>
<!-- ConnectionPingTimeout is optional: defaulted to 30000 -->
<ConnectionPingTimeout value="30000"/>
<!-- TcpNodelay is optional: defaulted to 1 -->
<!-- possible values: 1 (tcp_nodelay option set), 0 (tcp_nodelay not set) -->
<TcpNodelay value="1"/>
<Host value="apis23"/>
<Port value="14002"/>
<XmlTraceToFile value="1"/>
</Channel>
<Channel>
<Name value="Channel_2"/>
<ChannelType value="ChannelType::RSSL_SOCKET"/>
<CompressionType value="CompressionType::None"/>
<GuaranteedOutputBuffers value="5000"/>
<Host value="localhost"/>
<Port value="14002"/>
</Channel>
The DefaultConsumer was set to Consumer_3, so my EMA consumer app connected to the host listed in Channel_1. When the ADS in Channel_1 went down, my app switched to another provider running on localhost as expected.
