VxRack SDDC Overview (Part 1)

I have been doing a lot of investigative work recently with VxRack SDDC and i would like to give you an overview of the platform architecture  and how it all fits together.

VxRack SDDC is a hyper-converged platform from Dell-EMC that allows scalability and flexibility and is aimed at the large and extra large customers with large numbers of VMs and users. The solution is co-engineered by Dell EMC and VMware  and is made up of pre-loaded software with compute, storage and networking components.

The solution is powered by vCF (VMware cloud foundation) and provides an easy path to building out a VMware software-defined data center.

VMware Cloud Foundation includes : 

VMware vSphere

VMware NSX

VMware vSAN

VMware SDDC Manager

At the center of the solution is SDDC Manager and lifecycle management (LCM). These components enable the solution to be a fully automated deployment, including configuration and patching & upgrades of components

Current Minimum Config

8 nodes

Current Maximum Config

24 nodes in each rack (either all flash or all hybrid)

8 cabinets max (total of 192 nodes)


If you are just purchasing one rack then there are two Cisco 9372’s which function as TOR switches and a Dell S3048 Cumulus switch that is the management switch. The management switch is used for OOB connections and the HMS (hardware management service) is also installed on the management switch.

For multiple racks, you must have Cisco 9332 spine switches in the second rack


The first four servers on each physical rack are used for the management domain. The SDDC manager creates a single vSAN volume spanning all hosts in the cluster.


Screenshot taken from VMware Cloud Foundation Overview and Bring-Up Guide

The management domain contains the following VM’s

  • SDDC Manager
  • NSX Manager
  • vRealize Operations
  • vRealize Log Insight
  • vCenter Appliance
  • Two external PSC’s

If you have multiple racks then there is a management domain incl an SDDC manager on each rack. The SDDC manager on the first rack is the primary node and the others are secondary nodes. If the primary SDDC manager node fails then one of the secondary nodes will take over.

All racks are part of the same SSO domain and utilize the PSC’s that are located on the first rack, PSC’s are not deployed on the second and subsequent racks.

vRealize Operations is deployed on each rack but vRealize Log Insight is only deployed on the first rack.

Next we will take a look at at the VIA (VMware imaging appliance) and the system bring up procedure ….

Further Reading on VxRack SDDC






EHC available on VxRail

Support for EHC on VxRail was introduced as part of EHC release 4.1.1. This marks a watershed moment in EHC’s evolution as it is now available to customers of all sizes and also features an automated installation (automated installation only available on VxRail for now).

Supported services in this release include the following :

  • BaaS (backup as a service)
  • Encryption as a service
  • Single site protection

There is a four host minimum configuration and the traditional EHC Pod’s (Core, NEI and automation) are created as resource pools in the VxRail cluster. The reason for requiring four hosts instead of three is to ensure that you can suffer the loss of a storage node without affecting storage integrity.

EHC on VxRail allows you to start small and grow your hybrid cloud environment as your needs increase. It is simple, scalable and efficient.

The diagram below depicts the EHC architecture on a VxRail appliance.


If you want to see how hybrid cloud can be of benefit to you , there is Further documentation available here :



Click to access h15928r-ehc-4-1-1-concepts-architecture-sg.pdf

Click to access h15927r-ehc-4-1-1-reference-architecture-ra.pdf