Every time a vendor releases a new hypervisor, it’s always more reliable and stable than all the previous versions and certainly better than the competition. But was the previous version all that bad?
Of course with the addition of more and more advanced features it becomes more and more difficult to create a reliable and stable product simply because of the immense amount of code and the interdependency between all the different components. VMware has always had a dedicated hypervisor and with the release of ESXi they further reduced the code base of vSphere ESXi to minimize the attack surface. This also reduces the amount of code to patch which further improves reliability, stability and security.
Last week I visited a customer who, much to my surprise, still ran some VMware ESX 2.5 servers. According to the customer the servers ran fine and they had never had any problems.
When we opened the console, we found out that these ancient ESX 2.5 servers have had an amazing availability during the last 4 years.
Check this out!