On Friday, 05/17/2002 at 12:25 EST, [EMAIL PROTECTED] wrote:
> Greetings all;
>
> But regardless of all these grand features,
> lacking PAV are we still not limited to ONE i/o
> operation per os-visible spindle at a time?
>
> os-spindle = the physical device address we
> talk to regardless of VM minidisks or any
> Shark internal magic.
Yes. Without PAV, each os-visible device number can have only one
outstanding I/O at a time. Multiple physical paths only allows the
channel subsystem to select which channel ("wire") will be used to
communicate with the device. Multiple paths plus PAV gives you the
highest level of parallelism available.
Things will be a bit different with zSeries FCP (SCSI) as it is attaches
to a "multi-drop" FC fabric, but I'll let others with more expertise on
FCP comment on that.
Alan Altmark
Sr. Software Engineer
IBM z/VM Development
