What is VxRack – VxFlex Rack And VxRack SDDC.

What is VxRack – VxFlex Rack And VxRack SDDC.

1. VxRack SDDC

What is VxRack? VxRack is not a single product. It is a software-defined solution with two portions; VxRack Flex and VxRack SDDC. It is all built on x86 PowerEdge servers.

VxRack SDDC uses VMware Cloud Foundation software (this runs your whole solution/cloud) built on VMware vSAN for its software-defined storage and VMware NSX. VxRack is a little similar to VxRail and you could ask where the differences are? Let’s have a look

Mostly the VxRail is a single node you can add or buy to you customized solution and VxRACK SDDC is a full engineered rack solution that I don’t see on their site as a product anymore. It looks like it is only VxRAIL now (Oct 2019). VxRail is also the more popular one and sold more units up to now (Oct 2019). It is also a rack-scale HCI system running the complete VMware Cloud Foundation stack (vSphere, vSAN, NSX, vRealize Suite and SDDC Manager) for the fastest path to implementing an SDDC. VxRack SDDC does not offer the full flexibility of configurations available with VVD on VxRail such as choice of networking and custom configurations.

As the VxRack SDDC is not seen on their portfolio anymore like lots of other EMC products in the past we can just as well stop discussing it as it will probably fade away…

A newer picture that describes the while portfolio as of Oct 2019

2. VxRack Flex

VxFlex integrated rack (formerly VxRack FLEX) is built upon Dell EMC’s software-defined storage application, VxFlex OS (former ScaleIO). With this solution, you use the VxFlex OS block storage technology and can use the hypervisor of choice or even bare metal Linux servers. Except Nutanix AHV. They support Nutanix with another product on HCI in their XC family.

You have something they call the “Server SAN/2- layer”. This is where the block storage is not a SAN but is separated and separately managed from the compute resources. A node can have up to 46TB of space.

Hyper-converged config

Servers host both applications and storage and it provides maximum flexibility and easier to administrate. Maintenance of servers impact both storage and compute

Two-layer config:

IN two-layer, SDC and SDS run on different nodes and can grow independent of each other. Similar structure to traditional SAN. Support organizations that prefer separation between storage and application teams. Allows scaling of storage needs separately from the application servers. It has got a new 100Gb Switch for the aggregation layer.

Storage-only config:

Access to OS partition may still be done “regularly”. The SDC exposes VxFlex OS shared block volumes to the application. VxFlex OS data client (SDC) is a block device driver. The SDS owns local storage that contributes to the VxFlex OS storage pool. VxFlex OS data server (SDS) is a service.

With VxFlex You have nodes that run the VxFlex OS called VxFlex ready nodes. According to Dell EMC, you can scale IOPS into millions while maintaining sub-millisecond latency. It uses a new, additional storage pool layout using a much finer storage allocation units of 4KB. This is besides existingmediumm Granularity (MG) storage pools using 1MB allocation units.

You still have the standard Dell EMC’s products in the VxFlex like Avamar, Datadomain, and RecoverPoint. Cisco switches are still used and Dell switches will be used somewhere at the end of 2019.


These are all outstanding products for a variety of use cases. One thing I always respected about Dell or EMC or even Dell EMC is their after-sales support. I will never shy away from any customer looking to buy Dell EMC hyper-converged.

Cobus Smit – 3 Oct 2019

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