Going by the book, the upgrade process is precisely defined and should be followed in a specified order and manner whenever possible. In real life, other options and challenges always exist that might come into play in your organization. If you want to upgrade to vSphere 5.1 with the least possible headaches, you should perform the following steps in their precise order:
Read moreIn addition to hardware and performance considerations, there are other significant changes that will affect your upgrade and your use of vSphere 5.1, especially if you have more than one vCenter. There is a new Single Sign On service that increases security and control by allowing the software components to communicate with each other through a secure token mechanism. Depending on the size and complexity of your installation, there may also be a changed setting for the vCenter Server Administrator(s) of your organization.
Read moreIf you are upgrading to ESXi 5.1, there are some important facts that you should consider first. Upgrading involves many stages and processes that must be performed in a specific order. Many of these processes are one-way and do not provide a “back button.” If you do not use care and consideration in your upgrade plan, you could possibly lose important data and configuration, and potentially even lose contact with your servers. Understanding how to upgrade properly will ensure that you endure as little downtime as possible on each of your vSphere components.
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