In SMF record type 42 (hexadecimal 2A), subtypes 15 to 18 include statistics generated by VSAM RLS:

• Subtype 15: VSAM RLS storage class response time summary

  Look for a low read-hit rate in the coupling facility or a high false-invalidation rate, either of which points to a lack of space in the coupling-facility structure.

• Subtype 16: VSAM RLS data set response time summary

  Look for a low read-hit rate in the coupling facility or a high false-invalidation rate, either of which points to a lack of space in the coupling-facility structure.

• Subtype 17: VSAM RLS coupling facility lock structure usage

  The key measurement in this subtype is the number of false contention events. False contention happens when the hash code calculated for an entry collides with that for another entry. This can happen purely by accident because of the way the hashing algorithm works; however, false contention events also occur if the lock structure is too small.

• Subtype 18: VSAM RLS coupling facility cache partition usage

  Monitor the read-hit counter as a proportion of the number of reads, the number of read misses with directory hits, and the number of cross-invalidations due to directory-entry reclamation or due to local cache-vector replacement. These numbers can be symptoms of insufficient space in the coupling facility.

Related reading: For more information about SMF records, see z/OS MVS System Management Facilities (SMF).