Sql-server – SQL Server on CentOS using CAL licensing

The best thing you could do is read the VMWare guide "SQL Server on VMWare Best Practices Guide". This holds all the information you need. However...

1. Unless the instance is configured as a "wide VM", taking vCores from each socket, then you won't see 2 NUMA nodes. With Hyperthreading enabled, then you're only using the cores on one socket. (3.3.4 NUMA Consideration).

2. From the best practices guide: "VMware recommends setting the number of cores per socket to one when allocating virtual CPUs to VMs on the vSphere platform. That means that a VM that requires 8 CPUs will have 8 vCPUs with 1 core each." (3.3.5 Cores per Socket). Test this yourself though.

3. Where I'm working, the answer is "it depends". Some instances we leave it enabled, and some we don't. However... "VMware recommends enabling Hyper-threading in the BIOS so that ESXi can take advantage of this technology." (3.3.3 Hyper-threading)

4. If there are going to be no other instances on the host, then it's not as big a factor as if there's going to be more than one instance. It would be of benefit to have those allocated to separate sockets if you're looking to maximise performance. Unfortunately, you'd need to do quite a lot of testing and data capture to make an objective determination - I haven't found anything from VMWare specifically relating to this.

Go through the entire guide and read it: http://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/solutions/sql-server-on-vmware-best-practices-guide.pdf.

Other considerations are checking power schemes, because these can throttle CPUs so low that you get very poor performance, even from the best CPUs you can afford.

The following two articles make it clear that VMware will present a virtual NUMA configuration to the guest OS that is optimal. Accordingly, the number of sockets that are configured on the VM are more or less irrelevant as to the number of NUMA nodes. If the actual hardware has at least 8 cores in a NUMA node, then VMware is only going to present one NUMA node to a guest that has 8 CPUs, regardless of the VM's socket count.

Does corespersocket Affect Performance?

Virtual Machine vCPU and vNUMA Rightsizing – Rules of Thumb

Determining NUMA node boundaries for modern CPUs contains two helpful quotes that show that, even on hardware, number of sockets is not always equal to number of NUMA nodes:

When we originally did this analysis, the common multi-core processors were dual core or at most quad core. On these chips, the hardware manufacturers divided the NUMA boundaries into cores, rather than sockets. But it appears that that configuration is not the same for the larger multi-core (6, 12, etc.) chips.

and

In short, don’t assume that your NUMA boundaries are divided into cores – it very much depends on your specific CPU architecture.

I also ran across an TechNet article,Soft-NUMA (SQL Server), stating that each socket is usually represented by one NUMA node, but it doesn't explain when it wouldn't be.

You also might check the BIOS of the hardware to ensure that NUMA is enabled. I would be surprised if it was disabled, but I've learned through my career to never assume that someone didn't do something completely irrational.

Answers to your questions:

1. Given the evidence at hand, yes since both SQL Server and Windows are telling you that there is only one NUMA node, and we have some documentation from sources at VMware that it will present the optimal vNUMA configuration to the guest, which will be one NUMA node as long as the guest is configured with less than or equal to the amount of cores in the hardware sockets, and the number of sockets presented to the guest is irrelevant.
2. If the system architecture is telling the OS that there is one NUMA node, then there is one NUMA node and that is best because all CPUs are using the same memory. If it were actually two NUMA nodes but SQL Server only sees one, then yes, it would impact performance for anything that runs parallel.
3. The CPU architecture, which in turn dictates the mainboard architecture. On VMs, the NUMA configuration presented to the guest is determined by virtualization host (VMware, Hyper-V, etc.).