> Alan McDonald wrote:
> ...
> > I understand VMware can nominate single or multi core use.
> > Not sure if a declaration of single core use in VMWare is
> > transparent to Firebird since the VMWare may still broker
> > requests for CPU time to any of the 4 cores depending on
> > load.
>
> I've only used virtual machines over VMware Workstation and
> Server editions - but I imagine the ESX edition should be
> much the same, just faster (less overhead).
>
> The number of CPUs declared for the VM is what Firebird will
> see - if you host has that many. (eg: I am running a quad-
> core hardware in front of me and the entire virtual OS sees
> just the one processor that was specified for the VM... and
> when I specify a second it sees two processors. The system
> info reports the correct Intel identifier for the quad-core
> but it does not seem to see more cores/processors than the
> VM tells it to.)
>
> See this unanswered thread of mine that shows some performance
> comparisons (not related to Firebird specifically but you
> should get the idea) running over VMware Workstation v6.5:
>
> http://communities.vmware.com/thread/205351
>
>
> > Does anyone have experience here as to whether I can stick
> > with SuperServer (which is what it is at this time) or if
> > I need to switch to Classic to make best use of the FB
> > service. If the FB super sees thru the VMware core
> > switching, this may be to the detriment of performance.
>
> As far as my own experience goes the rules for Firebird remain
> unchanged. What the VM gives it is what it will see, so
> Classic may be better for multiple CPU, Super for single CPU.
>
>
> One of the things highlighted with the performance testing I
> did was just how much CPU can be taken up by the VM in dealing
> with disk and network access. I would be curious to see
> similar stats from ESX.
>
> --
> Geoff Worboys
> Telesis Computing

thanks Geoff, A bit of reading there. My client has been collecting stats
for a few months now. They've moved about 80 servers in now but my first
move will be with a relatively low load server, so no doubt I will be
watching carefully.
Alan