Memory numa node not evenly distributed

Question

I have two numa node on my sql server on linux . But I found that in sys.dm_os_memory_clerks, and even dbcc memorystatus() not having numa node 1 memory information .

Answer 1

As per your below image and output from sys.dm_os_memory_nodes

You do not have 2 NUMA nodes. The Node ID 64 will not be counted as NUMA node.

EDIT: Answer to follow up question

but I have 2 node_id on select * from sys.dm_os_nodes

Sys.dm_os_nodes show you NUMA nodes created by SQLOS while sys.dm_os_memory_nodes shows that created of soft NUMA, done by engine. The structure of physical NUMA can be altered by soft numa. Also if you look BOL doc for sys.dm_os_memory_nodes it says

Nodes are created per physical NUMA memory nodes. These might be different from the CPU nodes in sys.dm_os_nodes.

Plus see the output you posted for DMV sys.dm_os_nodes. For node_id 0,1 they have same memory_node_id as 0.

To further understand see SQL Server: Clarifying The NUMA Configuration Information, in this blog see section I have a non-NUMA system and SQL Server Still Shows NUMA - why?. This section has detailed answer to your question.

To further confirm run sp_readerrorlog 0,1,'Node configuration: node'. It will return information like

2011-11-09 12:38:01.38 Server Node configuration: node 0: CPU mask: 0x000000000000000f:1 Active CPU mask: 0x000000000000000f:1.
2011-11-09 12:38:01.38 Server Node configuration: node 1: CPU mask: 0x000000000000000f:0 Active CPU mask: 0x000000000000000f:0.

EX: Above output says system has 2 NUMA nodes.

Answer 2

Hi @sakuraime ,

I also think that there is only one physical numa node in your system.

According to the results by querying sys.dm_os_sys_info on your instance, the softnuma_configuration=1, this means the Automatic soft-NUMA was enabled on this instance. And the column numa_node_count : Specifies the number of numa nodes available on the system. This column includes physical numa nodes as well as soft numa nodes.

Each socket is represented, usually, as a single NUMA node. 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.
More details please refer to the MS doc : Soft-NUMA (SQL Server).

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