Nutanix AHV Max Cluster

There is no max cluster size.  (or was it 250 nodes? ;)) 

But dont make them to large as LCM will takes ages to finish. And the risks of multiple nodes down will increase with larges clusters. 

In the Support Portal there are theoretical configuration maximums to keep in mind. 

Go to Documentation → Configuration Maximums. 

But as Jeroen said: In theory there is no max cluster size for AHV clusters. 

For ESX on AOS there might be some limitations to be considered. 

hi guys ,thanks for the answers.

I tried to access this file, but i dont have access to it. Can you please provide me some links with this official statement for unlimited cluster size ?

The current maximum cluster sizes are documented on the Nutanix Support Portal under the “Configuration Maximums” section. These list the currently tested and supported configuration maximums. 

For AHV, the maximum cluster size as of 2023-03-14 is 32 nodes per cluster. https://portal.nutanix.com/page/documents/configuration-maximum/list?software=AHV&version=AHV-20201105.30398_6.5

In the past, this was documented as unlimited because there was no theoretical guard rail. However, it’s impossible to test a cluster of infinite size, so changing these to an integer value that aligns with tested numbers seems more rational to me.

In practice, you will often find your max cluster size is smaller than 32 because of other practical constraints as discussed in the Nutanix Validated Design. https://portal.nutanix.com/page/documents/solutions/details?targetId=NVD-2099-Hybrid-Cloud:cluster-design.html

Dear @bbbburns,

can you also provide documentation with max cluster size for ESX and AOS?

is it also 32? or does anything change for these ones?

Kind regards,

Vladimir.

bbbburns wrote:

 

Hello @bbbburns ,

I noticed that the maximum number of hosts per cluster in ESXi on AOS is 48, compared to the maximum number in ESXi on VMWARE, which is 64. Could you please explain what are the reasons for which we have less hosts per cluster when we use AOS?

Thank you in advance,

Adrian

The short answer is that the maximum cluster size documents what Nutanix has tested and what Nutanix supports as a result.

The longer answer is that so many factors go into choosing the maximum cluster size. The Hybrid Cloud Reference Architecture has a great section about this called “Choosing the Optimum Cluster Size”. 

If you factor in maintenance windows, upgrades, failure domains, power, cooling, and network ports, you might find out that the operationally optimum size for a compute & storage cluster is far smaller than the advertised maximum of just a hypervisor cluster.

Hello @bbbburns ,

Thank you for your answer.

Therefore, if my understanding is correct the information on your website saying that: “Nutanix Maximum cluster size: same as Nutanix cluster size” shall not be understood as “no limitation on the number of the hosts in cluster”, but in the sense that the maximum cluster size depends on the selected hypervisor.
Also, it follows that if we choose to implement a Nutanix AHV virtualisation solution with more the 32 nodes, then the configuration will not be stable and Nutanix will not guarantee the functionality of such solution.
We were considering creating production ready highly available AHV cluster with 48 or more physical nodes where we would accommodate both VMs and Kubernetes for which we would be providing file.

Thank you in advance,

Adrian