James, As a generalization, queuing for a volume from the same LPAR will increase as you increase the time that the volume is busy. If you have 9x3390-3 that at some point in time are 5% busy then you will probably see very little IOSQ time. Fold them into 1x3390-27 and it will be 45% busy and you will likely see an increase in IOSQ time.
I agree with the IBM presenter. Cache will not make a difference unless something changes the hit ratio. You really need one of the three varieties of PAV if you are going to fold volumes at this ratio in an unplanned manner. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On > Behalf Of james smith > Sent: Tuesday, November 04, 2008 3:43 AM > To: [email protected] > Subject: [IBM-MAIN] Performance Question - Dynamic PAV > > we have a customer panicking because an IBM presenter 'suggested' that > you > should not use Mod-27 devices for critical data UNLESS you have hyper > PAV > installed as you are likely to see problems with IOSQ times. Not sure > about > the validity of the comments so I thought I would seek out opinions on > the > list. He may just have been plugging the DS8000 box which comes with > hyper > PAV....... after all it was a 'dog and pony' show. > > Jim S. > > ---------------------------------------------------------------------- > 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 ---------------------------------------------------------------------- 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
