ESX Virtual Hosting is Not Ideal if:
- You require Mac OS, because it isn't supported by ESX. Instead, you should pick an OS that is either Microsoft Windows or one of the various flavors of Linux, including Ubuntu, OpenBSD, & CentOS.
- You don't know how to secure your server from malicious users, and you don't have the budget to hire a professional to do it for you. If you don't secure your guest OS, it can become compromised like any dedicated server -- virtual or not. You will need a minimum a firewall (software or hardware), a web application filter (such as mod_security), and an intrusion detection system (IDS) for your guest OS to be considered secure.
- You don't have a clear game plan, because adding a load of virtual servers will only add to the administrative work. You should know ahead of time how these new virtual machines will be administered. You need a proper consolidation strategy to ensure that the virtual machines fit within your organizations server policies and compliance standards. After the game plan is in place, utilizing VMware's templates will be an excellent way to create many virtual machines in minutes instead of days, and it can help in keeping deployment headaches to a minimum.
- You haven't measure the workload of each server you will be moving to an ESX hosted platform. You need to estimate the number of virtual resources you will need before deploying the virtual machines.
- You believe that the hosting company can use ESXi -- which is free -- and you want a super low price for your hosting package. In actuality, VMware requires that a hosting company become a VMware Service Partner and pay VMware a monthly fee for the rights to host other companies. Therefore, hosting companies, VM Racks included, must charge a reasonable fee that includes the monthly payments to VMware and can still achieve a reasonable profit.
By considering each of these scenarios, hopefully you can start to see if virtualization is right for you, and what steps you might need to take before virtualizing your servers.