There are 3 types of Nutanix nodes:
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An HCI Node is the most common kind of node. It is heavily equipped with all three components: processing capacity (CPU), memory (RAM), and data storage capacity. An HCI node can run any kind of supported hypervisor.
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A Storage Node only runs the Nutanix AHV hypervisor. These nodes have a bare minimum of processing and memory capacity however, as the name suggests, have plenty of storage onboard.
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A Compute Node only runs the Nutanix AHV hypervisor. Logically, these are nodes that have minimum storage onboard but are powerful compute and memory devices.
We are going to take a look at storage nodes in this post.
Storage Nodes (sometimes referred to as “Light Compute” Nodes) are nodes that only use AHV as their hypervisor. Due to their nature no user VMs should be run on these nodes. You will still see a CVM. CVMs are integral to Nutanix architecture as they process all storage input-output requests. Simply put you must have a CMV on each node.
The typical use case of a Storage Node is to expand storage capacity in a cluster without the need to buy additional hypervisor licenses for ESXi or Hyper-V. Storage Capacity provided by the Storage Nodes is added to the existing cluster seamlessly.
Storage Nodes increase storage capacity, improve performance, and resilience. RF replicas (typically) are placed on storage nodes allowing more capacity on HCI nodes for local IO. These Storage only Nodes can be added to the Nutanix clusters running ESXi, Hyper-V, and of course AHV.
As of Nutanix Foundation v4.0, “any” model node can be imaged as a Storage Node via the ‘bare metal’ imaging method. While this is true for the NX models, some of the OEM manufacturers have limitations on the supportability of particular models as Storage Nodes. Therefore, check with the OEM manufacturers before deploying into the production environment.
What is the difference between “Storage Heavy Nodes” and “Storage Nodes”?
'Storage Node' is the term that should replace 'Light Compute' & 'Storage Only’. A "Storage Node" must run AHV as the hypervisor. It usually has lower RAM and CPU resources, (enough to run the CVM and other Nutanix services only).
'Storage Heavy' means ANY node that contains a high capacity drives that can also run ANY hypervisor (ESXi/Hyper-V/AHV, or Xen). A "Storage Heavy node can also run guest VMs and workloads. Effectively, it is a normal HCI node that has a greater storage capacity.
To take a look at the steps on how to add a storage only node to your existing cluster, take a look at:
Want to take a look at a similar post for compute only nodes? Give a read to https://next.nutanix.com/discussion-forum-14/what-are-the-nutanix-compute-nodes-37488