> With ample dynamic PAV, there should be no measurable performance differences. Without ample PAV, then it depends. 'Ample' PAV means a zero IO queue depth. > You don't change a base volume to a PAV volume. PAV is simply another logical path to a volume. The application hasn't a clue. You define the base units starting from zero working up. The PAV 'alias' is defined starting at the highest UCB working down. When you vary a base unit offline, the PAV goes into a free pool and should eventually be reassigned. Vary a unit online, and one or more PAV will be assigned when/if WLM thinks they are needed. > Not a Shark issue AFAIK. That is, what ever makes sense now does so on the Shark. With PAV, perhaps somewhat less of an issue on the Shark. Note: depending on your configuration, you may not have a large enough UCB universe to use all of the raw space available. That is, you will have to define a mix of -3's, -9's, and possible -27's. If, for example, you define all mod-3's, you could run out of UCB's before you run out of space. Do your math carefully, and don't forget about upgrades.
(I use the term 'UCB' loosely.) HTH and good luck. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Kittendorf, Craig Sent: Friday, January 13, 2006 2:14 PM To: [email protected] Subject: Migration to Shark We are migrating from Amdahl DASD to a Shark (Model 800). No one here has experience with this. A DBA asked the following questions: What are the performance differences between volumes defined as MOD-3, MOD-9, MOD-27? What are the implications of changing a volume to a PAV volume? What type datasets/databases, if any, are required to be on their own volumes? I just need some generalities. Thanks, Craig ---------------------------------------------------------------------- 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
