We have a project this year to move lot of physical SQL Servers, starting with medium critical servers onto Virtual machines.
Generally on physical boxes we have a large count of logical processors, for example 80. Now when moving to VM we get 64 vCores/vCPU.
My understanding is: it's ok to be on low vCores/vCPU in VM till the time their speed is faster. I mean clock speed compared to one on physical.
This bought up an interesting debate with my colleague on how above behaves differently between servers where the majority of load is either single threaded queries vs parallel ones.
Following are a few questions:
How true is above?
Is there a way we can determine even approximately the servers where the queries are running serially vs parallel? I mean a way to say that my SQL Server has 70% queries which just run single threaded or parallel?