I had a discussion at the Dutch VMUG yesterday about the ReadyNode configurations for vSAN ESA. The discussion was about how difficult it was to select a host and customize it. It was then that I realized that most people hadn’t noticed yet that there is an easier method (or lifehack as my kids would say) when it comes to selecting your server model. How does that work? Well, let me show you!
First, let’s take a look at the vSAN ESA ReadyNode Hardware Guidance Table. The table below shows you what the node capacity is for each profile from a storage, CPU, memory, and networking perspective.
Now if you look at the table you will see that as the “profile” number goes up, so does the capacity for each of the various components. This is actually what provides you with a lot of flexibility in my opinion. If we take Dell as an example, but the same applies for most vendors on the current list, and we select “vSAN-ESA-AF2” and look at the list of options we see the following:
- PowerEdge R650
- PowerEdge R6515
- PowerEdge R750
- PowerEdge R7515
Now, if we look at “vSAN-ESA-AF8” next, which is the highest profile, we see that we only can pick 1 server model, which happens to be the PowerEdge R750. If we then look at the difference between the hosts selected for each profile a few things stand out:
- vSAN-ESA-AF2 has an Intel Xeon Silver 4314, while vSAN-ESA-AF8 has a Platinum 8358
- vSAN-ESA-AF2 has 512GB, while vSAN-ESA-AF8 has 1024GB
- vSAN-ESA-AF2 a 25Gbps NIC, while vSAN-ESA-AF8 has a 100Gbps NIC
- vSAN-ESA-AF2 has five 3.2TB NVMe devices while vSAN-ESA-AF8 has twenty-four 3.2TB devices
Now if I look at the KB article which explains what you can, and cannot change, something stands out, most of the components can be modified/customized. For instance, for CPU you can go to a higher core count and/or higher base clock speed! For memory, you can go up, same for storage devices (as long as you stay within supported limits), etc etc.
In other words, what is the difference between a vSAN-ESA-AF2 and a vSAN-ESA-AF8? Basically the expected workload, the performance, the capacity. This ultimately results in a different configuration. Nothing, at this point in time, stops you from selecting the “lowest” vSAN ReadyNode Profile and spec it as an “AF4”, “AF6” or “AF8” from a CPU stance, or from a storage/memory capacity point of view. If you want to have some more flexibility, try selecting a smaller profile, select the host type, and increase the resources/components where needed!
When you start exploring the options it may seem complex, but when you look more closely you will quickly realize that it actually isn’t that complex, and that it actually provides you with a lot of flexibility, as long as you stick to the rules and pick supported components!
Andrea Scarabelli says
Hi Duncan, great post as always!
What about adding 10GbE nic cards not for vSAN ESA traffic? Just for VM traffic for example…
Is it supported? I’m thinking about if it could lower the total cost of the infrastructure.
Duncan Epping says
Yes, fully supported.
So ESA is not suitable for smaller ROBO locations, which is really a pity. It looks so much more promising than the OSA architecture. But 512GB per host is just insane. Currently our ROBO locations just have 128GB and and 10-20 VMs.
Duncan Epping says
The first few releases ROBO/Edge is definitely the first usecase. OSA works perfectly fine for that. The team is working on optimizing the stack for other use cases though.