Hy,

Personnaly, I'm used to start with a CentOS VM with 20Go for disk and 2Go as RAM and 2 cores. Most of my customers have about 30 concurrent access. From time to time we upgrade to 4Go of RAM and it's really sufficient.

Hope it could help,

regards

regarding virtualization: we run on a KVM qemu virtual machine using qcow2 images. It has proven to be very usefull to work with "overlay images" whenever something new is being installed and commit them from time to time. Especially as we are pretty new in all of this it is nice to have such a feature. I am not an expert for virtualization at all so I can't compare really, but so far KVM/qemu works just fine for us.

One thing I haven't found out yet is how to access a KVM VM locally without using ssh or any other newtork service. In case you have messed up a VM's network it would be very useful (actually essential) to be able to just log in to your VM's console session from the command line of your host. I couldn't figure out how that works with KVM yet though.

saludos

Thank you very much!!