A user with the UAUDIT attribute set will log ALL successful USS classes, regardless of the AUDIT and LOGOPTIONS.
Changes made from CSM v5.1 to CSM v6.0 to the method for validating and performing file system mounts at startup might result in increased in SMF 80 record creation. Depending on the RACF Configuration for auditing and logging, the number of successful DIRSRCH and FSOBJ records also could increase.
The recommendation is to ensure that the UAUDIT Attribute is not assigned to the user profile assigned to the MSMTC STC. If auditing is required for this STC, you can explicitly set LOGOPTIONS for the DIRSRCH, DIRACC, and FSOBJ classes to control which class needs to be logged. You may also want to consider adjusting the SMF BUFSIZE if the additional logging results in SMF buffer shortages during MSMTC startup.