The performance of a single DF/DSS job using OPT(4) will be better than OPT(1). "N" concurrently executing DF/DSS jobs, each specifying OPT(4) may not be a "good thing" for overall performance - depending on channel configuration, make and model of I/O devices, etc. - for sufficently large values of "N".
Performance quant's standard answer #1: "It depends" -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- This is a PRIVATE message. If you are not the intended recipient, please delete without copying and kindly advise us by e-mail of the mistake in delivery. NOTE: Regardless of content, this e-mail shall not operate to bind CSC to any order or other contract unless pursuant to explicit written agreement or government initiative expressly permitting the use of e-mail for such purpose. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- "O'Brien, David W. (NIH/CIT) [C]" <[EMAIL PROTECTED]> Sent by: IBM Mainframe Discussion List <[email protected]> 06/13/2006 10:32 AM Please respond to IBM Mainframe Discussion List <[email protected]> To [email protected] cc Subject Re: DFSMSdss Performance Question As it was explained to me years ago, IBM is a very conservative company and the defaults tend to ensure that the smallest configuration will be able to run. As an example VSE was shipped to allow a single userid to run at a time. As far as OPT 1 vs 4 is concerned. I've always run with 4 and never noticed a performance hit. With older DASD and 4.5mb bus and tag cabling, a hit might have been noticeable and people who I respect have told me not to use OPT(4). With the newer technology, I think OPT(4) ought to be SOP. Just my opinion. -----Original Message----- From: Steve Flynn [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 13, 2006 10:25 AM To: [email protected] Subject: Re: DFSMSdss Performance Question On 13/06/06, Knutson, Sam <[EMAIL PROTECTED]> wrote: > Thanks! The OPT(4) is something I should have remembered but it was > pretty late. I did consider PARALLEL but it's not "automagical" and I This OPTIMIZE(4) thing is a new one to me - I'm not a storage person so I've never come across it... Is there any reason these days for having the product default to OPTIMIZE(1) - when would one ever let that parameter default? -- Steve Despair - It's always darkest just before it goes pitch black... ---------------------------------------------------------------------- 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
