Configure SMX connections

Server Multiplexer Group (SMX) is a communications interface that supports encrypted multiplexed network connections between servers in high availability environments. SMX provides a reliable, secure, high-performance communication mechanism between database server instances.

Reduce latency between servers

You can reduce latency between high-availability servers by increasing the number of pipes that are used for SMX connections between the servers. Set the SMX_NUMPIPES configuration parameter to the number of pipes.

Obtain SMX statistics

You can use the onstat utility or system-monitoring interface (SMI) tables to view SMX connection statistics or SMX session statistics.

To view SMX connection statistics, use the onstat -g smx command.

To view SMX session statistics, use the onstat -g smx ses command.

Encrypt SMX connections

Use the ENCRYPT_SMX configuration parameter to set the level of encryption for high availability configurations. If you set the ENCRYPT_SMX parameter to 1, encryption is used for SMX transactions only when the database server being connected to also supports encryption. If you set the ENCRYPT_SMX configuration parameter to 2 , only connections to encrypted database servers are allowed. Setting ENCRYPT_SMX to 0 disables encryption between servers.

Set the wait time for SMX activity between servers

You can set the SMX_PING_INTERVAL and SMX_PING_RETRY configuration parameters to adjust the interval that secondary server in a high-availability cluster waits for activity from the primary server. Use the SMX_PING_INTERVAL configuration parameter to specify the number of seconds in a timeout interval, where a secondary server waits for activity from the primary server in an SMX connection.

Use the SMX_PING_RETRY configuration parameter to specify the maximum number of times that a secondary server repeats the timeout interval that is specified by the SMX_PING_INTERVAL configuration parameter if a response from the primary server is not received. If the maximum number is reached without a response, the secondary server prints an error message in the online.log and closes the Server Multiplexer Group (SMX) connection.

Compress data through SMX connections

You can specify the level of compression that the database server uses before sending data from the source database server to the target database server with the SMX_COMPRESS configuration parameter. Network compression saves network bandwidth over slow links but uses more CPU to compress and decompress the data.


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