When vSphere 4 became available I was keen to upgrade all of my hosts and vCenter servers to start testing features like Fault Tolerance, Site Recovery Manager, and vCenter Linked Mode e.t.c. The host upgrade went smoothly using VMware Update Manager. Similarly, the upgrade of all vCenter servers was also without issue. A short while after, I needed to add RAM to a group of hosts and all was fine until I booted the first host post upgrading it's RAM.
I wanted to install some DRAC 5 cards into each of my Dell PowerEdge 2900 VMware ESX hosts, so I decided to VMotion off the Virtual Machines onto other hosts in the cluster before shutting down the node. The first Virtual Machine migrated without a problem but when I tried a second I received an error stating the there was a CPU incompatibility between the host and the Virtual Machine.
I have been using VMware ESX for quite a while now and while the technology is a brilliant concept every now and then I find a small problem or pitfall that always seems to bug me! I have a 3 node ESX cluster that I implemented in my work office and was working on configuring a 5 node cluster when I noticed an issue with VCenter (formally Virtual Center) that had occurred in both environments. It seemed that for no apparent reason when I rebooted the server running VCenter the 'VMware VirtualCenter Server' (or 'vpxd' windows service name) service failed to start. This was kind of annoying, more so knowing that the new 5 node setup was going to a datacenter where people would be less likely to spot that it hadn't started after the reboot of the server running VCenter!
I use VMware ESX 3.5 and Virtual Center 2.5 since implementing it at my current workplace. Like many sysadmins I regularly keep on top of patching. I manually patch my ESX hosts when I see fit after pulling updates through Virtual Center. Subsequently, I recently applied the latest update (3.5 u2 or update 2) to all ESX hosts. As a frequent reader of The Register I was later surprised to learn of a bug where people had encountered issues when booting or VMotioning Virtual Machines on or after 12th August 2008.