-----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of McKown, John Sent: Thursday, March 04, 2010 12:31 PM To: IBM-MAIN@bama.ua.edu Subject: Re: Defrag
> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:ibm-m...@bama.ua.edu] On Behalf Of Mark Pace > Sent: Thursday, March 04, 2010 12:23 PM > To: IBM-MAIN@bama.ua.edu > Subject: Defrag > > Each day I run a Compress, Release, and Defrag on each volume > in my SMS DASD > Storage group. Some of the volumes still remain pretty > fragmented. Is > there a way to defrag the Storage Group? > > -- > Mark Pace Hum, we don't even bother. We have set things up so that almost all our datasets are multivolume, via the DATACLAS. And by using DVC (Dynamic Volume Count) and so on. The DASD is so fast any more that we don't think it is worth the time to do defrags on volumes. Oh, and we try to keep a fairly good amount of "head room" in the Storage Groups as well. <SNIP> But how does this solve problems for NON-VSAM / non-EXTENDED data sets? 16 extents and you are done (on a volume). How does this reclaim space in the VTOC (I don't really care, but I can see why one might, even with indexed VTOC). I had asked a related question some time ago and I don't recall any one addressing it. I know that we are all [probably all] running with RAID. But since a real device is being emulated, we wind up with the problems that the VTOC recognizes (even though, virtually, the data may be side by side in an actual single extent). Regards, Steve Thompson ---------------------------------------------------------------------- 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
