I’ve pondered myself how much time, resources, and hardware (and if you’re an enterprise the cost of licenses and software that goes along) and when should I say “when” to virtualizing?
Typically virtualizing should stop if
- If you have no secondary domain controllers, directory services or anything that requires authentication, in case something happens to the “hypervisor”
- If the vendor says you can’t use such
- If licensing is too cost prohibitive (most often licensing for virtualization has a different cost structure – and don’t tell me to go FOSS)
- If the operating system or software is dependent on external devices. Assuming you have a 1U rack server, you only have up to two PCI cards, and assuming you have just 2 to 4 USB ports that can be mounted to a specific virtual appliance, and also factoring in other dependencies like audio cards, FireWire cards or ports, etc.
- MANAGEMENT: This for me is the dealbreaker when to stop virtualizing. Management workstations are essentially boxes that connect to say the VMware machines, your networking gear, your legacy PBX, and may also be a catch all machine to be a TFTP server to do upgrades, etc. In my environment, it’s currently virtualized, but given instabilities of the network sudden changes to the baremetal and what is on and what is off and what’s on that machine vs another, it may not be a bad idea to have it on it’s own box.
If you are a small workgroup, high end notebooks or decommissioned laptops that can support current operating systems that works in your setup could be a solution. I’ve done this with my mothers old Toshiba and ran Windows Server 2003 to work as a domain controller, plus DNS and DHCP on a sub PIII, and 256meg RAM. All MacBooks (not going to recommend PowerBooks or iBooks given it’s age for actual production use) can run OS X Server, and the more newer ones can run it’s daemon equivalent (the $19 copies) as well. As I would recommend, the daemons released after Lion, use with caution, reliability is only as good as your specs and ensuring your Mac is not being used as a primary desktop.
Virtualization is all the rage, it’s best to play it safe and not go too crazy.