Bob, On reason why 3390-54 may have higher response time than 16x3390-9 is that the underlying volume is striped over less physical disk drives.
Ignoring wide striping, in most DASD volume layouts a single volume is spread over two, four or eight disk drives. One 3390-54 will there have 2 to 8 physical disk drives backing it, whereas the 16x3390-3 could 16 times as many disk drives (32 to 256 HDD). How many drives a workload is spread over with 3390-3 will depend on your logical device layout, but there is a natural "flattening" of the back end IO load with smaller, well distributed volumes. If this is the problem you will see a larger disconnect time in the 3390-54 response time. If you are seeing IOSQ time then you need to look at your HyperPAV or PAV allocation. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On > Behalf Of Lester, Bob > Sent: Monday, March 19, 2012 3:57 PM > To: IBM-MAIN@bama.ua.edu > Subject: [IBM-MAIN] DASD Mod9/Mod54 > > Hi Folks, > > With todays' modern disk arrays, is there any reason (z/OS based or other) > that response time for my Mod54s is consistently higher than for my Mod9s? > > Assume identical workload against each, single array with multiple LCUs. > RMF says the LCUs are pretty well balanced. Single image. Pretty simple > setup. > > Thoughts? > > Thanks! > BobL > > mailgate3.oppenheimerfunds.com made the following annotations > --------------------------------------------------------------------- > This e-mail transmission may contain information that is proprietary, > privileged and/or confidential and is intended exclusively for the person(s) to > whom it is addressed. Any use, copying, retention or disclosure by any > person other than the intended recipient or the intended recipient's > designees is strictly prohibited. If you are not the intended recipient or their > designee, please notify the sender immediately by return e-mail and delete > all copies. OppenheimerFunds may, at its sole discretion, monitor, review, > retain and/or disclose the content of all email communications. > --------------------------------------------------------------------- > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send email to > lists...@bama.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
