On Wednesday, 01/24/2007 at 09:46 CET, Rob van der Heij <[EMAIL PROTECTED]> wrote: > While standing at the virtual white board... Since CP can already > provide some form of virtual QDIO devices, it would seem more > attractive to enhance that into virtual FCP. The good thing about that > is also that it allows CP flexibility in reordering the I/O requests > and perform them in a way that makes sense on a global level. Some > interaction between CP paging and this virtual FCP might be very > attractive. > The scope of things like WWPN in Linux would be local to the z/VM > system, and up to CP to interpret (e.g. to distinguish between swap > space and real data).
This comes under the heading "Be careful what you ask for - you might get it." :-) At first glance that looks really attractive. However, when you actually start wanting to manage your storage and performing end-to-end storage provisioning, you find that the question "Who is connected to what?" is difficult to answer correctly when there are two different views of the world. WWPNs are really [fabric] network addresses and, like vMACs on layer 2 VSWITCHes, things work better and with fewer surprises when we avoid synthetic addresses. That isn't to say we couldn't have vFCP with N-PIV WWPNs reserved for a particular user, but we already have that now, essentially, by dedicating the correct RDEV to the user. Alan Altmark z/VM Development IBM Endicott
