Planning
Upgrading
New clients
Up and running
Consolidated Backup
The upgrade was also greeted with applause from users of the VMs as they noticed improved performance thanks to our being able to allocate four CPUs to some VMs, where previously only 2 CPUs had been possible. However, without an extra ESX 3 server and VirtualCenter we were not able to take advantage of DRS and HA, both highly attractive features for data centre operations. For example, HA enables VirtualCenter to monitor VMs and restart them if they should crash. While this does not happen frequently, our experience is that this feature would have prevented several hours of downtime over the last year. Similarly, DRS enables server resources such as RAM and CPU time to be allocated to groups of VMs in such a way that should a particular ESX 3 server be unable to meet that requirement, one or more VMs would be automatically migrated to other ESX 3 hosts so that each VM got as close a possible to its resource allocation. In addition, ESX 3 supports a new "maintenance mode", which can be activated from the VI3 client software. When a server is put into this mode, its VMs are migrated to another ESX 3 host using VMotion, provided another host is available, so that hardware maintenance can be performed on the original ESX 3 server without any downtime to VMs or loss of services to their clients.
Verdict
Excellent. VMware is unique in providing a server virtualisation platform that does not require special virtualisation-enabled processors or modified guest operating systems. The features for automated monitoring and management of virtual machines are also outstanding.
