> Consider what MPG offered: Increased performance. Moving to a more > powerful machine plus the ability to RESERVE or LOCK guest pages helps > make up for the loss of MPG. Plus, the limit of 6 preferred > guests makes > it less interesting for server consolidation, IMHO.
The limit of 6 preferred guests has always puzzled me -- it always seemed more a political decision (thou shalt not make LPAR look bad) than a technical decision. Was it that, or was there some serious technical problem that prohibited just marching on up through storage computing offsets until you run out of storage? > Intellectually, from the purist's perspective, I'm sure the > loss of MPG > hurts, but the reality is that of those who run zLinux, the > vast majority > run in LPARs. So, the z990 changes nothing in this respect. Although it's probably useful to point out that that decision is driven more by use of IFLs forcing LPAR mode than any real necessity for LPARs. It's understandable why IFLs require LPAR mode, but it's not a particularly good reason to eliminate basic mode operation. I still don't understand the z990 channel system well enough to argue that point, but I do wonder whether it's substantially more complicated than dealing with the split channel system that the 3084 and it's ilk had. We seemed to deal with that well enough w/o losing basic mode. The psychological argument you mentioned can be continued to point out that creating a new virtual machine in a basic mode system is even less committment of resources than an LPAR requires, and with VM still trailing z/OS in some of the hardware management functions, shops running w/o z/OS really do much better operationally running in basic mode and not ever disturbing the machine configuration. -- db
