If you are not aware yet, a major bug has been revealed in ESX 3.5 and ESXi 3.5 Update 2.  Apparently, the beta was coded to expire on August 12, 2008 and this code failed to be removed from the actual release.  Details are available in the VMware Knowledge Base and This Topic on their forums.  You might also checkout This Post on Matthew Marlow’s blog for more information.

On the morning of the 12th, I was greeted with several errors like this one in the logs for our ESX cluster:

VMware finally released the patch really late Tuesday night, which, unfortunately kept me up most of the night getting our cluster patched.  It involved setting back the clock on all of the hosts so Vmotion would work, manually migrating VM’s off of a host, going into maintenance mode, applying the patch via the command line, then migrating the VM’s back.

VMware is one of my favorite companies and it know for delivering rock-sold, enterprise-class products, so it really disappoints me that they would let something like this slip through the cracks.  Imagine how many hundreds of thousands (Maybe millions?) of VM’s this affected.  They do seem to be committed to fixing their mistake and making things right.  You can check out the Letter From Their CEO for more info.