> > The practical example below will explain it completely: > > > > 1) we take 4 common modern computers - CoreQuad + 8 GB Memory. > > 2) we assemble a standard Linux cluster with 16 cores and 32G memory. > > 3) and now - we run the only one virtual guest system, but give it ALL > > available resources.
If the guest isn't aware of this discontinuity then performance will really suck. Generally speaking you have to split jobs anyway, the same as you would on a regular cluster, the SSI just makes migration and programming a little easier. If you don't believe me then talk to anyone who's used large SSI systems (e.g. SGI Altix) - these systems have dedicated hardware assist and interconnect designed for SSI operation and you still have to be fairly selective about how you use them. > What you're describing is commonly referred to as a Single System > Image. It's been around for a while and can be found in software-only > verses (pre-Xen VirtualIron, ScaleMP) and hardware-assisted (IBM, 3leaf). Or better still do it at the OS level (e.g. OpenSSI). Paul