Re: [OT] Re: Hercules - how to get a zVM OS (legally bought!) and put it on a VM under Hercules?
On Sat, Aug 22, 2015 at 11:24:54AM -0400, Stephen Powell wrote:
> As I see it, there are three sides to this question: the practical side,
> the legal side, and the technical side. I will address them in that order.
> First, the practical side. Hercules is a software emulation of a mainframe,
> not a real mainframe. It adds a tremendous amount of overhead. Debian
> under Hercules under amd64 is *way* slower than Debian running directly
> under amd64 using the same hardware. I suspect you will find that
> the performance of your z/VM systems is not adequate for production use,
> even when Hercules is running on the fastest amd64 processors available.
> But the only way to find out is to try it, I suppose.
It doesn't help in this specific instance, put qemu can emulate System z
now and provides much better performance than Hercules. That being said,
it also relies on virtio devices, which means that it isn't of much use
to run z/VM on it. (Plus the emulation might be incomplete and/or IBM's
products might depend on undocumented instructions.)
Technically using Hercules is probably your best bet[*]. It should be able
to do MIPS similar to your existing z800 on contemporary x86-64 hardware.
(You'll certainly know for how many MIPS your existing machine was
sized and Hercules does display them.) You might need to be careful with
relation to I/O, of course.
Kind regards
Philipp Kern
[*] There's also z/PDT. But well, that one really need discussions with IBM
and all.
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