Someone recently asked my opinion about best practices for
virtualization—specifically, what should be virtualized.
Here's my answer: It isn't so much about what to virtualize
as what not to virtualize.
Nearly anything can be virtualized, but does it always make
sense? Despite the abstraction from the kernel, all virtual
machines (VMs) require physical resources. Memory, processor,
storage, input/output per second (IOPS), and bandwidth are
requirements for any computing technology. Virtualization is no
different.
Compare virtual machines with physical machines
The big difference between virtual and physical machines
is that virtual resources are just pooled physical resources. This
allows for more efficient use of your resources. You are less
likely to have a virtual machine that is more powerful than it
needs to be. Instead of using a fraction of the memory and
processor, as you often see happening with physical machines, a VM
uses only what it needs. On the
