We have a UCS B200 M3 Dual Proc with a total of 16 cores and HT turned on for 32 logical CPU's. In a test scenario we are powering on 50 single proc W7x64 VM's and it is taking over 30 min to complete the boot cycle. Ready time jumps to over 200% on most of the VM's within esxtop.
In esxtop we can see that only 8 cores are are pegged at 100% along with the associated HT pCPU's. The remaining 8 cores on the second physical processor hover at 20%.
The 50 VM's have HT sharing set to the default of Any and CPU shares are set to Normal. What would cause this to happen? I would expect all 16 cores to be fully utilized, or at the very least more than 20%.
We also can see that it is not a storage issue as we are running on a dedicated SSD array with latency remaining below 3ms during the "boot storm"