z/OS V2R1 Questions and Answers - Priority, RACF Certificate Checks, ISPF Regex, z/OSMF, VLF Cache, DCM, zDAC, zFS, Symbol Updates

Sep 25, 2026

Uploaded by Rizky

z/OS V2R1 Questions and Answers compiles guidance on system behaviors and configuration options. Topics include CF structure serial rebuild prioritization, RACF health checks for impending certificate authorization and configurable look-ahead windows, ISPF FIND/CHANGE regular expression support, and z/OSMF integration possibilities with IBMLink and Eclipse. Additional coverage explains VLF cache object age health checks, DCM channel-path assignment for FICON performance, zDAC interaction via HCD and IODF activation, zFS V4/V5 usability and conversion expectations, and symbol update mechanisms using SETLOAD with IEASYMxx.

LanguageEnglish

CategoryExam

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

CF Structure Rebuild Priority

RACF Health Check: Impending Certificate Authorization

ISPF Edit Regular Expressions in FIND/CHANGE

z/OSMF and Integration Questions

Eclipse Plug-in for z/OSMF

VLF Cache Object Age Health Check

DCM and FICON Channel Enhancement

zDAC Interfaces with HCD and IODF Activation

zFS File Systems: Conversion to V5 and Usability

Symbol Updates and SETLOAD IEASYM

z/OS V2R1 Questions and Answers Q. CF Structure Rebuild Performance Enhancement-how do you specify the priority/how do we prioritize what get rebuilt first? A. This question pertains to the z/OS 2.1 "Serial rebuild" line item, in which the rebuild of multiple structures is done serially instead of in parallel and in a defined order so that the more important structures get rebuilt first. z/OS defines a default prioritization for the structures , so that by default , we rebuild first the structures that z/OS likes--XCF signaling structures , lock structures , etc. If you don't like this prioritization, you can define your own using new keywords in the STRUCTURE definition in the CFRM policy, for each structure. This overrides the z/OS default prioritization. There are two stages of rebuild; system (e.g. , XCF signaling) structures and “other structures.” The system structures are rebuilt in a fixed order that you cannot change, and they will have QUASTRSYSRECPRTY set in IXCYQUAA; and, if message IXC360I is issued after a DXCF command, a system-determined priority will be displayed. The other structures will be rebuilt according to their priority in the CFRM policy, using the new RECPRTY keyword. Q. About the RACF Health Check for "impending certificate authorization". How far out is it checking and can those parameters for the expiration dates be altered or changed? A. The check (RACF_CERTIFICATE_EXPIRATION) defaults to 60 days, but can be set by parameter to zero (0) to 366 days. This check is designed to detect that a trusted certificate connected to one or more key rings is due to expire within a time period you specify. This is intended to help alert you of pending certificate expiration in time to enable you to take an action to prevent applications that rely on valid certificates from failing. Q. For the “ISPF Edit support for regular expressions in FIND and CHANGE commands” – what does this mean? Are these UNIX terms? Are these commands Posix or Perl standards/format? A. Regarding the regular expression support in the ISPF editor, this is implemented using the z/OS XL C/C++ regcomp() and regexec() functions. ISPF uses the extended regular expression support provided by regcomp() . These functions are implemented based on the XPG4 standard, which is a POSIX standard. For information on the regcomp() function and supported regular expression see: [http://publib.boulder.ibm.com/infocenter/zos/v1r13/topic/com.ibm.zos.r13.bpxbd00/regc](http://publib.boulder.ibm.com/infocenter/zos/v1r13/topic/com.ibm.zos.r13.bpxbd00/regc)[opp.htm\#regexdf](opp.htm#regexdf) Q. Regarding z/OSMF-Client asks if there is any interface, now or planned for the future, between z/OSMF and IBMLink A. Not at present, and no plans that I know of, but I believe you can add your own links to the z/OSMF navigation tree. Q. Also about z/OSMF-is there a plug in for Eclipse for z/OSMF ? A. z/OSMF's User Interface is web-based, and Eclipse is workstation-based. There's one connector I know of. Q. For the Health Check for VLF cache object age – can we provide more information about what this means? How early does it let you know about an object in the VLF? A. This health check helps you manage the amount of virtual storage used by the virtual lookaside facility (VLF) . This is designed to enable you to specify a minimum age for VLF-cached data and notify you when the time objects that have been cached fall below that minimum. This is intended to help you choose the best settings for the MAXVIRT parameters for each class of objects specified in the COFVLFxx member of parmlib to improve overall system performance. Q. Client wants information about what DCM is and what is the enhancement provided for FICON channels? A. DCM dynamically assigns channel paths to disk control units as needed to meet demands for bandwidth. With DCM you assign a (minimum) number of "unmanaged"channels for availability purposes and then specify a num

FAQs

How is priority determined for CF structure serial rebuild, and can the rebuild order be customized?

z/OS uses a default prioritization for structures and rebuilds them serially so more important ones are rebuilt first. If custom priority is required, define new keywords per STRUCTURE in the CFRM policy to override the default.

What does the RACF_CERTIFICATE_EXPIRATION health check do, and how far in advance does it detect expiring certificates?

It detects when a trusted certificate connected to key rings is due to expire within a time window you specify. The default is 60 days and it can be configured from 0 to 366 days.

What is meant by ISPF edit support for regular expressions in FIND and CHANGE commands?

ISPF implements regular expression support using z/OS XL C/C++ regcomp() and regexec() functions. It uses extended regular expression support based on the XPG4 POSIX standard.

Sep 25, 2026

Uploaded by Rizky