Be sure to carefully read what Alan wrote: I/O queuing in CP on the RDEV. That is: if you have a guest (like Linux, z/OS, or even SFS and DB2/VM) it will start only one I/O at a time to a device (the architecture doesn't allow more). The guest can have a queue too (on its virtual device that is), CP's PAV support can't help here. The queue in the guest cannot be seen by CP's performance monitor. To profit of PAV, guests need PAV support themselves and you have to attach base plus alias addresses to the guest.
Futhermore: when dataspaces are used, CP's paging routines perform the I/O, and CP's paging doesn't use PAV... 2008/7/3 Bruce Hayden <[EMAIL PROTECTED]>: > > The z/VM 5.3 announcement letter states that it includes HyperPAV > support for IBM System Storage DS8000. So - if you have a DS8000, > then you have the dynamic PAV support. However, as far as I know, 5.3 > does not virtualize HyperPAV, so a guest can't use it directly, > although it can take advantage of VM's use of it for minidisk I/O. > > On Thu, Jul 3, 2008 at 10:01 AM, Imler, Steven J <[EMAIL PROTECTED]> wrote: > > Alan, > > > > I suppose the reason you say "Before you go to all that work ..." is > > because z/VM (unfortunately) does *not* support dynamic PAV. Which > > means the only way you can leverage or take advantage of PAV on z/VM is > > to hard code the PAV aliases in the DASD subsystem. > > > > (This is the reason we no longer have access to PAV volumes on our z/VM > > systems ... because no one wants to do the work configure the DASD > > subsystem when z/OS will do this all dynamically.) > > > > JR (Steven) Imler > > CA > > Senior Software Engineer > > Tel: +1 703 708 3479 > > Fax: +1 703 708 3267 > > [EMAIL PROTECTED] > > > > -- > Bruce Hayden > Linux on System z Advanced Technical Support > IBM, Endicott, NY -- Kris Buelens, IBM Belgium, VM customer support
