## 3.2.7.1 Collect System Information
The initial step is to collect information about the system and its topology.
Basic system information may be needed to identify available features in SAP HANA. In the SAP HANA Cockpit, the tile Database Information provides the initial information. This information is also accessible via the view (or public synonym) m_HOST_INFORMATION.
The example system shown here uses SAP HANA version HANA2, Rev 56 using SUSE Linux Enterprise Server 12 SP4 as operating system version (using Linux kernel 4.12.14-95.68-default).
The next step is to collect system topology information using the SAP HANA Database Explorer. The view m_HOST_INFORMATION delivers relevant information on the system topology. In this example, the system is equipped as below:
| Key         | Value                    | Explanation                                                                                                                                                                 |
|-------------|--------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| cpu_cores   | 88                       | The number of physical CPUs in the system.                                                                                                                                  |
| cpu_threads | 176                      | The number of logical CPU cores. Consequently, there are 2 hyperthreads per physical core on this system. Note on the IBM Power platform there can be up to 8 hyperthreads. |
| cpu_model   | Intel Xeon Gold 6152 CPU | Refer to hardware vendors' internet sites for specific details, for example: Intel Xeon Gold 6152 CPU                                                                       |
| mem_phys | 405394542592                  | This corresponds to approximately 400GB DRAMphysically available on the system.                                                                                                                 |
| os_name  | SUSE Linux Enterprise 12 SP04 | The operating system used on this host. Refer to the internet sites of operating system vendors for more specific details and to the SAP Note 2235581 - SAP HANA: Supported Operating Systems . |
build_version
2.00.056.00.1617904818
This is HANA 2, Rev 56.
| SOL Console 4 sql   | SOL Console 4 sql   | SOL Console 4 sql                   |                                                                                          |           |
|---------------------|---------------------|-------------------------------------|------------------------------------------------------------------------------------------|-----------|
| Raw Data            | Raw Data            | Analysis                            | Analysis                                                                                 | Analysis  |
| Rows (63)           | Rows (63)           | Rows (63)                           | Rows (63)                                                                                | Rows (63) |
|                     | HOST                | KEY                                 | VALUE                                                                                    |           |
|                     | 1d5866              | Cpu_summary                         | 88 (176)                                                                                 |           |
|                     | Id5866              | build_githeadcount                  | 503001                                                                                   |           |
|                     | Id5866              | name                                | SUSE Linux Enterprise Server 12 SP4                                                      |           |
| 10                  | Id5866              | Os_cpe name                         |                                                                                          |           |
| 11                  | Id5866              | ner_domain                          |                                                                                          |           |
| 12                  | Id5866              | mem Swap                            | 34359734272                                                                              |           |
| 13                  |                     | memory_map_area_limit               | 2147483647                                                                               |           |
|                     | Id5866              |                                     |                                                                                          |           |
| 15                  | Id5866              | hw_model                            | ThinkSystem SR9SO -[7XI2CTO1WW]-                                                         |           |
| 16                  | Id5866              | net_realhostname                    |                                                                                          |           |
| 17                  | Id5866              | sid                                 | NMO                                                                                      |           |
|                     |                     | os_ppms                             |                                                                                          |           |
| 18                  | Id5866              | name                                | LINUX_X86_64                                                                             |           |
| 19 20               | Id5866 Id5866       | sapsystem topology meminto          | 00                                                                                       |           |
| 21                  | Id5866              | build_gitmergetime                  | 2021-04-08 20.00.18                                                                      |           |
| 22                  | Id5866              | cpu_cores                           | 88                                                                                       |           |
| 23                  | 1d5866              | net_publicports                     |                                                                                          |           |
| 24                  | 1d5866              |                                     | 1048576                                                                                  |           |
|                     | 1d5866              | cputhreads                          | 176                                                                                      |           |
| 25 26               | 1d5866              | net_publicname                      |                                                                                          |           |
| 27                  | Id5866              | Umezone otfset                      | 7200                                                                                     |           |
| 28                  | Id5866              |                                     | CEST                                                                                     |           |
| 29                  | Id5866              | ssfs_masterkey_systempki_changed    | 2021-04-09 14.35.41                                                                      |           |
| 30                  | Id5866              | build_compiler                      | gcc (SAP release 20200227, based on SUSE gcc9-9.2.1-r275327-1.3.7) 9.2.1 20190903 [gcc-9 |           |
| 31                  | Id5866              | net ipv4 tcp_max_syn_backlog        | 8192                                                                                     |           |
| 32 33               | Id5866 Id5866       | build_gen                           | rel 4096                                                                                 |           |
| 34                  |                     |                                     |                                                                                          |           |
|                     | Id5866              | crypto_provider_version             | CommonCryptoLib 8.5.36 (Nov 5 2020) [AES-NI,CLMUL SSE3 SSSE3]                            |           |
| 35                  | Id5866              | build_cloud_edition                 | 0000.00,00                                                                               |           |
| 36                  | Id5866              | build_version                       | 2.00.056.00.1617904818                                                                   |           |
| 37                  | Id5866              | topology_mem_type                   | shared                                                                                   |           |
| 38                  | Id5866              | open_tile_limit                     | 39526120                                                                                 |           |
| 39                  | Id5866              | daemon_active                       | yes                                                                                      |           |
| 40                  |                     |                                     | none                                                                                     |           |
| 41                  | Id5866 Id5866       | crypto_fips_version crypto_provider | commoncrypto                                                                             |           |
| 42                  | Id5866              | mem_phys                            | 405394542592                                                                             |           |
To understand the NUMA topology in more detail, the monitoring views NUMA_NODES and NUMA_RESOURCES are available. SAP Note 2470289 mentions further options to analyze the NUMA topology and memory usage.
## Monitoring Views NUMA_RESOURCES
From these views one can learn that the system has four NUMA nodes with NUMA_NODE_IDs 0, 1 2 and 3. Every NUMA node has 44 logical cores, and as every physical core has two hyperthreads every NUMA node has 22 physical cores. The system memory is evenly distributed across these four NUMA nodes with 100GB of DRAM attached to every NUMA node. From m_NUMA_NODES.NUMA_NODE_DISTANCES or m_NUMA_NODES.NEIGHBOUR_NUMA_NODE_IDs one can reconstruct the NUMA node topology, that is how the cores of every NUMA node can communicate with other NUMA nodes to fetch data from another NUMA node or for work stealing.
As illustrated below, in this system every NUMA node has all the other NUMA nodes as neighbors, that is fully meshed via the blue connections between the NUMA nodes.
The system used in this analysis likely does not have strong NUMA effects because all NUMA nodes are directly connected with each other. When memory of one NUMA node can only be reached via multiple hops in the NUMA topology, we can expect a stronger NUMA effect. This is the case when certain NUMA nodes are not listed as neighbors of some NUMA node in view m_NUMA_NODES. Furthermore, systems with many NUMA nodes may require a dedicated "NUMA node controller' to connect islands of NUMA nodes which are connected with fast UPI links (as in the example above). This information is provided by the hardware partner or from the system specification.
It is important to analyze performance issues related to the system setup before proceeding with the analysis of the workload. Refer to the sections in this SAP HANA Troubleshooting and Performance Analysis Guide and SAP Notes for a starting point. The SAP HANA hardware partners also offer support in this step.
## Related Information
Examine the Workload [page 99] SAP HANA Administration Guide: SAP HANA Cockpit Getting Started With the SAP HANA Database Explorer SAP Note 2470289 SAP Note 2235581 m_HOST_INFORMATION m_NUMA_NODES System View m_NUMA_RESOURCES System View Certified and Supported SAP HANA Hardware Partners