There are two different vCenter Server editions, and which one you use depends on your needs and your budget. The...
less expensive edition, vCenter Server Foundation, licenses for $1,495 and can manage up to four ESXi hosts. VCenter Server Standard, which licenses for $5,995, can manage up to 2,000 hosts and 25,000 powered-on VMs. Beyond that, you can have up to 35,000 VMs registered within a single vCenter server. You can also run up to 10 linked vCenter servers, which comes in handy if you manage a large environment that spans across regions or countries -- you can have all vCenter servers and their inventory objects within a single console.
VCenter Server support options
Both vCenter Server editions come with two different support options: Basic and Production. The Basic support option offers technical support 12 hours per day within published business hours, Monday through Friday. The Production support option offers technical support 24 hours per day, seven days per week. One year of Basic support for vCenter Server Foundation costs $545, while one year of Production support costs $645; one year of Basic support for vCenter Server Standard costs $1,259, while one year of Production support costs $1,499. You also have the option to buy three years of support, which entitles you to support if problems arise, as well as free updates and upgrades. Weigh the importance of your infrastructure to decide which works best for you.
Different features for different editions
VSphere Essentials and Essentials Plus kits are both designed for the SMB market and contain vCenter Server. While both kits contain the same vCenter Server, which can only manage three hosts, Essentials Plus includes more features, such as vMotion and High Availability. Both vCenter Server editions can have up to three hosts with up to two physical CPUs each; you won't be able to configure VMs with more than eight virtual CPUs.
VCenter Server for Windows vs. vCSA
Originally, IT administrators had a choice between vCenter Server editions that ran on Windows and vCenter Server Appliance (vCSA). Both of these versions were able to manage the same number of objects and hosts. However, VMware recently made the decision to deprecate Windows-based vCenter.
This is a strategic move from VMware, which maintains that vCSA is superior to vCenter Server for Windows. VCSA integrates with vSphere Update Manager (VUM), a product that enables you to patch VMware environments, including hosts and VMs, within the same console. Windows-based vCenter also has a VUM component, but you need to install it on a separate Windows system.
It isn't always easy to learn a new Linux OS, but VMware has tried to smooth this transition by providing reliable tools that allow you to migrate from Windows-based vCenter to vCSA.
VCSA has a management UI that allows you to install patches, configure time synchronization and adjust some network settings. Beyond that, VMware has locked down this product so users cannot install other software inside.
Windows-based vCenter installations have been limited by the size and performance of the built-in Microsoft SQL Server Express database, but VMware vCSA uses PostgreSQL, which is an open source database platform. Admins can only view the database size and its performance. No configuration or optimization options are available, but none should be necessary.