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How to Improve RACF Performance (v0.2 - 2016)


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When hundreds and some times thousands of security validations occur every minute on the mainframe, performance and availability are paramount. In this session the presenter shows some different techniques that when implemented can help improve RACF performance, so that it does not become the source of your performance problems.

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How to Improve RACF Performance (v0.2 - 2016)

  1. 1. Delivering the best in z services, software, hardware and training.Delivering the best in z services, software, hardware and training. World Class z Specialists How to improve RACF performance Rui Miguel Feio – Senior Technical Lead
  2. 2. Agenda Conclusion Summary of what was discussed and key points to remember Questions Ask away any questions that you may have! Things to Consider Other things that you may consider when improving RACF performance and security Improve Performance Technical description of ways to improve performance in RACF Performance What is performance and areas that can help to improve performance in RACF ABOUT ME Brief description about the presenter
  3. 3. Who Am I? RUI MIGUEL FEIO • Working with RSM since 2010 • Working with mainframes for the past 17 years • Started with IBM as an MVS Sys Programmer • Specialises in mainframe security • Experience in other platforms Key facts: SENIOR TECHNICAL LEAD
  4. 4. Performance
  5. 5. Performance - how well a person, machine, etc. does a piece of work or an activity.
  6. 6. RACF Performance • RACF DB allocation • # RACF DBs • RACF Exits • SETROPTS • Global Access Table • RACLIST • RACF DB Maintenance • Processes • Procedures RACF
  7. 7. RACF Subsystem
  8. 8. Global Access Table (GAT) Improve performance: • Include “public” resources • Reduced number of entries to minimise time spent checking the GAT • Deactivate GAT checking in no GAT entries for a specific class Bear in mind: • Access granted via the GAT isn’t logged • An entry in the GAT supersedes any corresponding RACF resource profiles • Define equivalent profiles in RACF classes in case GAT becomes unavailable
  9. 9. RACLIST Improve performance: • RACLIST every RACF class you can • Alternatively use RACGLIST and GENLIST: • With GENLIST, RACF information is copied into real storage (ECSA) • GENLIST works best with frequently accessed profiles • RACGLIST reduces IPL time in a data sharing environment Bear in mind: • RACLIST copies RACF information into virtual space • Don’t refresh in-storage data too often • RACLIST and GENLIST can’t be used together • In most sites use of RACLIST is sufficient
  10. 10. SETROPTS • Applies to discrete non-RACLISTed profiles • Produces statistics of little value • Disable this by issuing SETROPTS NOSTATISTICS(*) STATISTICS(class_name) • Don’t audit frequent, unimportant events • Don’t use AUDIT(SUCCESS) on APPL profiles • Use dataset profiles’ AUDIT option instead of AUDIT(DATASET) • Don’t use LOGOPTIONS(ALWAYS) for frequently used RACF classes AUDIT(class_name) & LOGOPTIONS(option)
  11. 11. SETROPTS • Avoid using ERASE(ALL) • With modern DASD, DASD does the work and no CPU or I/O is involved which means the impact is minimum but… • Check this option with your Storage team ERASE(option) • To avoid producing excessive SMF records that may affect system performance, some sites opt for NOOPERAUDIT • If using System or Group wide OPERATIONS then OPERAUDIT should be enabled • Replace OPERATIONS by equivalent Storage Administration OPERAUDIT
  12. 12. System
  13. 13. System Data Blocks z/OS
  14. 14. System • Virtual Lookaside Facility • RACF may benefit from caching • Cached entities can include: • Logon credentials (ACEE) • Group Tree in storage • User Security Packets (USP) and UID/GID mapping • Speak with the Sys Progs team VLF Data Blocks z/OS
  15. 15. System • Enqueue Residence Value • Increase ERV in IEAOPTxx • Grants more CPU to any process with an enqueue on RACF • The default value is 500 • Recommended value is in the range of 40,000 to 50,000 • This will optimise performance to any enqueues to system resources • Speak with Sys Progs team ERV Data Blocks z/OS
  16. 16. System • Couple Facility • RACF DBs shared in a Sysplex can benefit from CF caching • Index and data blocks will be stored in the CF • Can use CF even for a stand-alone non-sysplex system • Ensure CF cache is large enough to hold all non-RACLISTed profiles • Speak with Sys Progs team CF Data Blocks z/OS
  17. 17. System • Global Resource Serialisation • Applies for 2 or more non-sysplex systems sharing a RACF DB in with no Couple Facility (CF) • GRS can convert RESERVEs to global ENQs • Each system is given exclusive control for one update request at a time: • Lock is only for the RACF DB • Lock is not for the DASD vol. • Solves the contention problems caused by the exclusive RESERVEs GRS Data Blocks z/OS
  18. 18. System • Resident Index Blocks (RID) • Always try using the max RIDs (255) • RIDs are searched very fast and reduce I/O to the RACF DB • Must be using the RACF DB name table (ICHRDSNT) • If you don’t use RID and ICHRDSNT your RACF has a very poor performance Data Blocks Data Blocks z/OS
  19. 19. System • A RACF DB has a single set of in- storage resident data block buffers • Split the RACF DB for highly active RACF DBs • Split into up to 99 RACF DB data set pairs (Primary/Backup) • Requires Sysplex wide IPL for change to the ICHRRNG table implementation • ICHRRNG is used to specify how profiles are distributed across the various RACF DB data sets RACF DB Data Blocks z/OS
  20. 20. System • High system usage and peak logon periods may cause I/O impact • Allocate RACF DBs on their own DASD volumes with no other high usage datasets on them • Speak with Storage team DASD Data Blocks z/OS
  21. 21. System • Reduce updates to last access date • Every time a user logs onto the system, RACF updates the “last- access” date and time • This info is used to enforce password change frequencies and perform automatic revokes • Occurs when an application passes its APPLID to RACF • RACF only needs to know the most recent date • APPLDATA field needs to have RACF-INITSTATS(DAILY) in the APPL class profile Access Date Data Blocks z/OS
  22. 22. System • Poorly designed RACF EXITS can degrade performance • Many access checks might be expected to fail before the authority is determined. • Preferably do not audit these failures • Make sure the RACF EXITS deal with these events without impacting performance EXITS Data Blocks z/OS
  23. 23. RACF Security Team
  24. 24. RACF Security team Tools Use tools that will help with the security role (e.g IBM zSecure, Vanguard) Collaborate Collaborate with other mainframe teams. Consider sharing ideas with teams of other companies Education Keep up-to-date with what’s happening in the mainframe realm RACF DB Maintain RACF DB; remove redundant profiles, userids, groups and Classes. Group Tree Review and remediate RACF group tree structure (e.g. RBAC) Processes Implement adequate security processes and procedures RACF Team
  25. 25. Other things to consider
  26. 26. Other things to consider Improve Security • Perform regular: • Security audits • Security penetration test • Vulnerability scannings • Consider: • Subsystems (DB2, CICS, …) • ISV products • Internal applications
  27. 27. Conclusion
  28. 28. In Conclusion… Strategy Define a strategy with the other teams on how to improve the systems, processes and procedures Measures & Targets To evaluate performance improvement you need to be able to measure and compare. Performance Analysis Performance team needs to get involved to help with the performance improvement Assessment Optimising RACF is not only a systems task; it is also a team effort. Assess who needs to be involved and what will need changing. Objectives The objective of improving performance needs to be take in consideration other aspects such as cost, effort, etc. Strategic Initiatives In a world evermore dependent on the technology, performance and security must go hand-in-hand. Strategy Map Once a strategy is defined, a ”map” must be made available to all parts to allow full implementation. Evaluation Evaluate the impact of changes in terms of performance and security and remediate accordingly if required.
  29. 29. Questions
  30. 30. Rui Miguel Feio, RSM Partners mobile: +44 (0) 7570 911459 linkedin: Contact