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SMF Recording Techniques

SMF records on individual minidisks that you reserve for this purpose. Reserved SMF minidisks reduce the number of I/Os required to record SMF data. This reduction of required I/Os increases throughput of the CA ACF2 for z/VM service machine.

Also, you can write records synchronously or asynchronously. When the CA ACF2 for z/VM service machine is recording data synchronously, FSWRITE performs normal CMS I/O. When recording data asynchronously, the *BLOCKIO IUCV system service performs the I/O.

SMF recording requires you to:

• Format the SMF minidisks with filemode 6 and 4K blocks. Completely allocate each minidisk to each SMF file with the CMS RESERVE command.
• Set the PRIOR operand of the @SMF macro to specify whether you need priority SMF recording.

  PRIOR=NO

  The CA ACF2 for z/VM service machine manages records enqueued for writing and issues a *BLOCKIO asynchronous write request for each block of SMF records.

  PRIOR=YES

  The CA ACF2 for z/VM service machine issues an FSWRITE synchronous I/O request for each SMF record. The PRIOR=YES setting provides a minimum of SMF data loss in case of a system outage or failure.