Bill, Cast your mind back to GTFPARS. This IBM FDP would build seek histograms using IEHLIST VTOC Listings as input to map the extents of the datasets on the volume.
CA-ASTEX does some very good IO level analysis. As with FASTDASD, CA-ASTEX intercepts every IO. I think that this replaced FASTDASD after CA bought Legent. It used to have a pretty good LRU cache modeler built in. I wonder if it still works and supports 512GB or more of cache? Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of > Bill Fairchild > Sent: Monday, May 03, 2010 8:27 AM > To: IBM-MAIN@bama.ua.edu > Subject: Re: [IBM-MAIN] How to analyze a volume's access by dataset > > 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 > > ---------------------------------------------------------------------- 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
