VSAM performance tuning is done by setting appropriate buffers. If you use SMS managed, it is easier.
Itschak On Fri, Mar 13, 2009 at 11:48 AM, Richards, Robert B. < robert.richa...@opm.gov> wrote: > CR+ and its VSAM Mgr component > > Bob > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On > Behalf Of Ward, Mike S > Sent: Thursday, March 12, 2009 5:09 PM > To: IBM-MAIN@bama.ua.edu > Subject: Re: VSAM files > > Thanks for the tip(s). > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On > Behalf Of Tom Harper > Sent: Thursday, March 12, 2009 4:06 PM > To: IBM-MAIN@bama.ua.edu > Subject: Re: VSAM files > > Mike, > > > > Such tools exist (I think McKinney Systems has one), but I don't think > you would want to use it in the manner you have described. Here's why: > > > > * CI/CA splits are not indicative of poor performance. If you > reorg such a file, the splits are likely to re-occur. > > * Total extents do not degrade performance on today's RAID > devices. > > * EXCPs are not recorded for many types of VSAM I/O, for > example, Media Manager and STARTIO. > > * Statistics kept in the VSAM catalog are stale and only updated > when the file is properly closed, perhaps never. > > > > I would study up on VSAM performance (there are some good sessions at > SHARE) and re-assess your criteria. Then, be thankful you only have > hundreds of VSAM files. I know of customers who have over a million VSAM > files. > > > > In general, VSAM performance problems are less related to the data sets > themselves and more related to the techniques used to access them, > buffers, LSR, etc. > > > > > ---------------------------------------------------------------------- > 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
