How many NUMA Nodes do I have?
A question that I get asked very often during my various SQL Server Consulting engagements is on how many NUMA nodes SQL Server is running on. Therefore I want to show you in today‘s blog post a few ways and techniques to find out how many NUMA nodes your SQL Server has.
For a general (deep dive) introduction to NUMA I recommend that you read the NUMA Deep Dive Series from Frank Denneman.
Windows OS Level
First I want to show you a few ways at the Windows OS level how you can find out how many NUMA nodes you have. The easiest way is to use the CPU view of Windows Task Manager. With the default setup Task Manager shows you how many CPU cores you have available.
As you can see from the picture, Windows also reports here the number of CPU sockets that you have available. Normally the number of CPU sockets corresponds to the number of NUMA nodes you have. If you want to be sure you can also change the display settings to the NUMA view.
After changing that the Task Manager shows you how many NUMA nodes you have available – in my case 4 NUMA nodes.
There is also the coreinfo.exe tool from the SysInternals tools which also reports how many NUMA nodes you have in your system. And this tool also tells you the latency times between the individual NUMA nodes.
SQL Server Level
When you don’t have access to the Windows Server itself, you can also use SQL Server to find out how many NUMA nodes you have available on your system. The easiest way is to look into the SQL Server Log, because during the startup phase SQL Server reports how many NUMA nodes were detected.
Alternatively you can also query the DMV sys.dm_os_memory_nodes, where SQL Server reports the available Memory Nodes. For every available NUMA node SQL Server creates one dedicated Memory Node (besides Memory Node ID 64, which is always present for the Dedicated Admin Connection).
Here you can also see that this SQL Server is running on a two-node NUMA system.
As you have seen in this blog post there are many different ways to find out how many NUMA nodes you have available on your system. Please feel free to leave a comment on how many NUMA nodes you are running SQL Server on.
Thanks for your time,