Since I joined Nutanix, I have heard from customers that they want to scale storage (capacity) separate to compute as they have done in traditional SAN/NAS environments.

I wrote an article a while ago about Scaling problems with traditional shared storage which discusses why scaling storage capacity separately can be problematic. As such I still believe scaling capacity separately is more of a perceived advantage than a real one in most cases, especially with traditional SAN/NAS.

However here at Nutanix we have locked ourselves away and brainstormed how we can scale capacity without degrading performance and without loosing the benefits of a Nutanix Hyper-Converged platform such as Data Locality and linear scalability.

At the same time, we wanted to ensure doing so didn’t add any unnecessary cost.

Introducing the NX-6035c , a new “Storage only” node!

What is it?

The NX-6035c is a 2 node per 2 RU block, which has 2 single socket servers with 1 SSD and 5 x 3.5″ SATA HDDs and 2 x 10GB NICs for network connectivity.

How does it work?

As with all Nutanix nodes, the NX-6035c runs the Nutanix Controller VM (CVM) which presents the local storage to the Nutanix Distributed File System (NDFS).

The main difference between the NX-6035c and other Nutanix nodes is that it is not a member of the hypervisor cluster and as a result does not run virtual machines, but it is a fully functional member of the NDFS cluster.

The below diagram shows a 3 node vSphere or Hyper-V cluster with storage presented by a 5 node NDFS cluster using 3 x NX-8150s as Compute+Storage and 2 x NX-6035C nodes as Storage only.

Because the NX-6035c does not run VMs, it only receives data via Write I/O replication from Resliency Factor 2 or 3 and Disk Balancing.

This means for every NX-6035c in an NDFS cluster, the Write performance for the cluster increases because of the additional CVM. This is how Nutanix ensures we avoid the traditional capacity scaling issues of SAN/NAS.

Rule of thumb: Don’t scale capacity without scaling storage controllers!

The CVM running on the NX-6035c also provides data reduction capabilities just like other Nutanix nodes, so data reduction can occur with even lower impact on Virtual Machine I/O.

What about Hypervisor licensing?

The NX-6035c runs the CVM on a Nutanix optimized version of KVM which does not require any hypervisor licensing.

For customers using vSphere or Hyper-V, the NX-6035c provides storage performance and capacity to the NDFS cluster which serves the hypervisor.

This results is more storage capacity and performance with no additional hypervisor costs.

Want more? Check out how Nutanix is increasing usable capacity with Erasure Coding!