How to tell how many more VMs can be added to a host or cluster?

Question

I have downloaded the vKernel vOPS vApp and see on the Environment Explorer page the capacity box on the right shows "You have room on 1 cluster to place up to 23 VMs".

Does this mean that is the maximum VMs or does that number indicate there is capacity for 23 more VMs?

sundling · Accepted Answer

It´s 23 additional VMs based on average utilization of your existing VMs. /Mattias

dwisby · Answer

Thank you sir. That is what I was hoping.

dwisby · Answer

Thanks, that would be much more beneficial. I appreciate the expeditious response. Thanks David Wisby

dwisby · Answer

What does the VM density information mean when it says Minimum 13:1 Maximum 13:1 and Average 13:1?

sundling · Answer

Thanks for the feedback, will consider to add 'additional' to clarify this in upcoming version. /Mattias

sundling · Answer

No, it's just stating min, max and average number of VMs currently (13 VMs per host in your case). Typically you want to have as high as possible to maximize ROI. /Mattias

sundling · Answer

Number of VMs per host. /Mattias

dwisby · Answer

So it has nothing to do with how many VMs can reside on a particular Host?

dwisby · Answer

OK, so I added 2 VMs to the cluster and the Capacity box shows 'You have room on 1 cluster to place up to 25 VMs', instead of 22. If it is indeed additional VMs that can be added, that number should be decreasing instead of increasing. Correct?

sundling · Answer

The calculcation for additional VMs is done every hour so it´s possible your current workloads have changed characteristics/utilization.

Average analysis period for this calculation is last 24 hours.

/Mattias

v.taillet · Answer

I can't understand the way of calculation

On a 5 hosts cluster, Foglight say we can add 0 VM.

But for a maintenance on another cluster, we have moved 25 VMs on that cluster.

So, if we were able to move and power on 25 Vms on that cluster, why Foglight said 0 ?

osterf · Answer

I also have problems to understand the way of calculation. We have a Cluster with 4 Hosts. The Average Analysis Period is set to 1 day. The result shows me that I can add 6 VM´s (average in CPU and Memory) for the Cluster.

On 3 ESX hosts I can add 6 VM´s and on 1 ESX host I can add 4 VM´s. What about the 6 VM´s for the Cluster? Can I add 6 VM´s and share them to a corresponding host or can I add 22 VM´s?

When I increase the Average Analysis Period I can add more VM´s after recalculation. Why?

Virtualization Infrastructure Management

How to tell how many more VMs can be added to a host or cluster?

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