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The size of a message data file will grow to a maximum size that is configured with the MAX_DATA_FILE_SIZE OMS configuration option, which defaults to 25 megabytes. When the active message data file maximum size has been reached, the message data file is closed, reopened for read-only access, and a new active message data file is created.
Message data files are deleted by an OMS Server clean-up process that runs periodically or when the OMS Server starts as part of the database validation. The OMS Server message data file clean-up process will analyze all the message data files to determine if they contain any undelivered messages. If an undelivered message is found in a message data file, that message data file - as well as any subsequent message data files - will not be deleted. When all messages have been delivered, the message data file is deleted. The time interval in which message data file clean-up is performed is configured with the MSG_CLEANUP_INTERVAL OMS configuration option, which defaults to 30 minutes.
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The OMS message database location is specified by the SPOOL_DIRECTORY OMS configuration option. The default directory is platform-dependent.
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OMS Server throughput depends largely on the performance of the I/O subsystem on which the message database resides. Each record written to the message data file is flushed to disk, so buffering has no effect on performance. For that reason, the OMS Server message database should reside on a sufficiently fast I/O subsystem. Precise hardware configurations are beyond the scope of this document. The OMS Administration Utility does include an I/O test command that can be used to test the performance of an I/O subsystem.
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