I recently created a bare metal (i3.metal) EC2 instance that I'm going to use as a farm for VMs (the guest VMs will be used for testing various cases). Because performance of the guest VMs is important, the specs of this EC2 instance are quite high: 72 vCPUs, 512GB RAM, 25,000 provisioned SSD iOPS. The host OS is Windows Server 2016.

On the guest VMs themselves, I've given each 16 CPUs (2 processors with 8 cores each) and 16GB RAM. All VMs are VMWare WorkStation v17.

However, performance of the VMs is dismal. Even with just a single VM running, from power on to Windows login screen prompt takes close to 10 minutes. These are essentially vanilla Windows 10 VMs so I would expect the power on to take closer to 60 seconds. I'm open to any suggestions on how I can get higher-performing VMs in this setup.

  • Not an answer, but if you use them for testing, do you do this 24/7? If not, may it not be cheaper to pay AWS only for a 16vcpu instance during the time you need it? – jdog Apr 8 '19 at 19:19
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    Curious why you need a large fast EBS volume when you have 16TB of very fast SSD storage? Backing up data, sure, but you probably don't need io1 for that. – Tim Apr 8 '19 at 19:50
  • By default after build I had an OS volume that was 860GB. I checked Disk Management and found 8 uninitialized 1.7TB volumes. I initialized one and moved one of my VMs to it and ran another startup test - unfortunately no change in performance. – user3342256 Apr 8 '19 at 20:48
  • Seeing interesting behavior now - if I lower the specs of the guest VMs to 4 vCPUs and 8GB RAM (from 16 vCPUs and 16GB RAM previously), the VMs start much more quickly (2ish minutes). However, they are immediately pegged at 100% CPU post-login. – user3342256 Apr 8 '19 at 21:54

So, if you are making any bare metal to host machine for vm's you have to tune it. To do so you need tuned-adm command if you want to execute predefine tunning, however still you need to fix some more stuff for production ready or to create test bed. Hope it will help you.

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