Got 5 hosts in a cluster, and stress testing them, so I have put 8x W2k3 VM's on one host each with 16GB RAM and 4vCPUs and created a rule so the must stay together and the DRS setting is set to Manual for VMotion so they cannot DRS off, on this host I have put another VM --no rules so should be able to DRS anywhere, and is setup as default cluster settings, all VM's can VMotion manually.
When I CPU stress the 8 big VMs the Host CPU goes to 100% as expected and stay on the host as expected, but the lone VM does not DRS off to one of the other hosts on the cluster even though the host is on it knees.
Any ideas, am I missing something as like I say all servers are VMotion ready and working, all networking is working, in fact everything is working except DRS across all the hosts --I am completely lost. 
DRS is enabled by the way and all hosts are fuly licenced. Weirdly though if I have another VM on the said host powered down and power it up the VM automatically powers up on another host, as if DRS is working.
This happens on vCenter 3.5 Update 3 with ESX Hosts 3.5 Update 3 & vCenter 3.5 Update 4 with ESX Hosts 3.5 Update 4
THIS IS DRIVUNG ME NUTS AS EVERYOTHER TIME I HAVE DONE THIS THE LONE VM MIGRATES BECAUSE OF DRS, NOTHING HAS CHANGED.
