We are looking at moving our ecommerce website to a VPS. If we run CentOS and additionally Apache, MySQL, and a few other things, how many slices will we need to start with? How does this compare to OpenVZ? Thanks.
For cpanel it is recommended to have 2 slices, on either kvm or openvz. You did not mention cpanel however, so if you are not running it, you probably can get away with 1 slice on either KVM or Openvz.
In all honesty your memory usage on openvz will be lower, because it is not loading the kernel into memory as part of the usage.
Slices can be added if it turns out you need more resources.
Right, we hadn't planned on cPanel. We've read your posts on why to choose KM/OpenVZ and really can't see which way to go. It would seem like KVM is more secure. We aren't aware of any kernel modules or change we will need, so KVM isn't a must have. If, down the road, we decide to add something that would require something like that, could we upgrade to a KVM server at that point/? Thanks.