-----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Rick Fochtman Sent: Wednesday, April 25, 2007 12:21 PM To: [email protected] Subject: Re: FW: Do we have to defrag MVS volumes on newer generation disk arrays?
Chase, John wrote: > Forwarded for a colleague.... <SNIPAGE> > >My guess is that we do, because it still looks like (E)CKD to z/OS. > >TIA, > > ------------------------------------------------------------------------ I'm inclined to agree; continue the DEFRAG operations. <SNIP> Is there some way to run a test of this and see if there is any performance improvement? I'm asking because the DASD is simulated/emulated behind cache. And isn't this why certain VSAM options are no longer required/supported? So if there is a certain amount of intelligent read-ahead into cache, would defragging actually accomplish anything more than correcting VTOC entries? Regards, Steve Thompson ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
