GTF traces the seek address (CCHR, et al.) stored in the IOSB but the post-processing to determine which of the data sets on the volume has each given traced CCHR within its allocated extents is non-trivial, and I don't know of anyone who has written such code, unless I did it and have forgotten about it. FastDASD, marketed by CA the last I heard, does all that by sampling, not tracing, the DASD addresses used by most access methods, then reads the VTOC to determine in which data set each I/O occurred. I used to be involved with FastDASD, and may even have added support for GTF input, but if so, it was too long ago for my mercury delay line memory cells to remember.
TMON/MVS, on the other hand, gets the CCHRs by intercepting I/Os rather than sampling z/OS control blocks. Its analysis is thus far more accurate, but the amount of data analyzed is much smaller than is capable with FastDASD. I'm not sure how unabridged the SMF records are; i.e., probably not all I/Os are accounted for, especially those done by the operating system and/or exotic subsystems using low-level access methods. Both TMON/MVS and FastDASD are capable of catching such SMF-avoiding I/Os as long as they are done by components that put the I/O's starting DASD seek address in the IOSB, but that is not required of authorized programs that do I/O. Bill Fairchild Software Developer Rocket Software 275 Grove Street * Newton, MA 02466-2272 * USA Tel: +1.617.614.4503 * Mobile: +1.508.341.1715 Email: bi...@mainstar.com Web: www.rocketsoftware.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Longnecker, Dennis Sent: Friday, April 30, 2010 6:20 PM To: IBM-MAIN@bama.ua.edu Subject: Re: How to analyze a volume's access by dataset TMON/MVS gives us that information for a real time snapshot. Can either start a summary or detail I/O trace and look at the trace once it is completed. I imagine a GTF I/O would be able to also get you that information, but since we have TMON, we use that. Dennis -----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of John Norgauer Sent: Friday, April 30, 2010 3:01 PM To: IBM-MAIN@bama.ua.edu Subject: How to analyze a volume's access by dataset Is there any software available that will show the access by dataset(or by CCHR) for a given volume? John Norgauer Senior Systems Programmer Mainframe Technical Support Services University of California Davis Medical Center 2315 Stockton Blvd ASB 1300 Sacramento, Ca 95817 916-734-0536 SYSTEMS PROGRAMMING...... Guilty, until proven innocent !! " JN 2004 ........ "Hardware eventually breaks - Software eventually works" anon ........ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
