Large corporations moving to a virtualized infrastructure for their systems and networks may have all the expertise needed already on hand. However, small and medium sized companies would do well to work closely with an IT consulting firm so they have guidance at every step along the way, beginning with one of the most basic steps of all: selection of an appropriate host server.
Depending on the server selected, companies may be able to place up to a hundred different virtual machines on the same physical host. A radically different host, however, may only be able to accommodate a few. Before selecting a server, companies need to get a handle on how many VMs they anticipate needing and using. Once that variable is pinned down, they can move on to considering four criteria that will help them evaluate if a given server will meet their needs.
1. Computing power
Additional computing power is relatively cheap these days. Many IT consulting firms advise companies to have at least one CPU core for every four VMs to be hosted. This formula assumes that the VMs will utilize a single CPU architecture.
2. Network connections
Most host servers should have at least four network interface cards. More will be required if the company wants to use network-based storage solutions such as iSCSI.
A host server should be supplied with as much RAM as feasible because each VM will be drawing on it. Best practice for managing VMs means giving them an exact allocation of memory that is equal to its true needs. Assuming that the host server has been generously supplied with memory, more RAM can always be reallocated later to VMs that need it.