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What is NUMA node SQL Server?
NUMA stands for Non-Uniform Memory Access. The purpose of NUMA is for Scheduler (CPU) to have faster access to memory. Each node will have its own memory controller and serves up to 8 CPU. CPU and Memory are partitioned at the hardware level to improve the access to memory. SQL Server is NUMA aware application.
What is soft NUMA?
The Automatic Soft NUMA logic considers logical CPU ratios, total CPU counts and other factors, attempting to create soft, logical nodes containing 8 or fewer CPUs each. SQL Error log: Automatic soft-NUMA was enabled because SQL Server has detected hardware NUMA nodes with greater than 8 logical processors.
How do I know if NUMA is enabled?
You can check it by using ESXTOP:
- Run esxtop.
- Press “m” to enter on memory statistics.
- Press “f” to change the fields displayed.
- Press “f” again to show NUMA related fields. If numa is enables, you will see values (like, 0, 1, 2, etc for each node) on the NHN column, like this image:
What is NUMA architecture?
Non-uniform memory access (NUMA) is a computer memory design used in multiprocessing, where the memory access time depends on the memory location relative to the processor. NUMA architectures logically follow in scaling from symmetric multiprocessing (SMP) architectures.
When to create soft NUMA nodes in SQL Server?
With SQL Server 2016 (13.x), whenever the SQL Server Database Engine detects more than eight physical cores per NUMA node or socket at startup, soft-NUMA nodes are created automatically by default. Hyper-threaded processor cores are not differentiated when counting physical cores in a node.
Where to find Numa configuration information in SQL Server?
When SQL Server starts up is outputs the NUMA information in the error log detailing its view of NUMA and provides DMV outputs to show the information as well. Here is the output from my 2 Processor Group system. A NUMA node can’t span a processor group so I am assured to have 2 NUMA nodes with CPUs associated with each node.
How many cores does a soft NUMA have?
When the detected number of physical cores is more than eight per socket, the SQL Server Database Engine creates soft-NUMA nodes that ideally contain eight cores, but can go down to five or up to nine logical cores per node.
What does numanode0 mean in SQL Server configuration?
Notice that ‘NumaNode0’ is shown. It is just a poor choice of wording and is exposing the same node 0 that SQL Server is using when you look at the DMVs for tracking the CPUs on the system within the scheduling node. Everything is technically correct that we have a single (1) memory bank associated with all the CPUs on the system.