HANA News Blog

Intel COD / SNC NUMA feature

Matthias Sander + Jens Gleichmann • 28. September 2023

Possible performance degradation or inconsistencies

Sub-NUMA Clustering by Frank Denneman

--Scroll down for English version


Es gibt ein Intel Feature mit dem Namen SNC bzw. COD. Dabei steht SNC nicht für Secure Network Connection, sondern für Sub-NUMA Clustering. COD steht hier nicht für ein Videospiel, sondern für Cluster-On-Die.


Diese Features werden bei neuerer Hardware eingesetzt und wird ca. seit zwei Jahren teilweise standardmäßig aktiviert (beispielsweise bei HPE).

Die Features dürfen unter keinen Umständen mit HANA verwendet werden. Neben Performanceproblemen können ebenso Inkonsistenzen auftreten!


Es wird ein phys. NUMA Node in zwei NUMA Nodes aufgeteilt. Bei einem unserer HANA Health Checks wird neben der Datenbank auch von Storage über Hypervisor und OS einiges überprüft. Bei einem Kunden, für den wir einen solchen Health Check durchgeführt haben, ist uns aufgefallen, dass der ESXi bei einem phys. 2 Sockelserver plötzlich 4 NUMA Nodes anzeigt.


Auf ESX Ebene kann dies mit dem folgenden Kommando überprüft werden:

echo "CPU Packages";vsish -e dir /hardware/cpu/packageList;echo "NUMA nodes"; vsish -e dir /hardware/cpuTopology/numa/nodes

Das Feature kann im BIOS deaktiviert werden (Beispiel HPE).

####################################################English#########################################################


There is an Intel feature called SNC or COD. SNC does not stand for Secure Network Connection, but for Sub-NUMA Clustering. COD does not stand for a video game, but for Cluster-On-Die.


These features are used in newer hardware and have been partially activated by default for around two years (for example at HPE).

The features may not be used with HANA under any circumstances. In addition to performance problems, inconsistencies can also occur!


A physical NUMA node is divided into two NUMA nodes. During one of our HANA health checks, not only the database but also the storage, hypervisor and OS are checked. We noticed at one customer that the ESXi suddenly shows 4 NUMA nodes on a physical 2 socket server.


At ESX level, this can be checked with the following command:

echo "CPU Packages";vsish -e dir /hardware/cpu/packageList;echo "NUMA nodes"; vsish -e dir /hardware/cpuTopology/numa/nodes

The feature can be deactivated in the BIOS (example HPE).

Source

2470289 - FAQ: SAP HANA Non-Uniform Memory Access (NUMA):

Is it possible to use sub-NUMA clustering for SAP HANA?

On BIOS/UEFI level it is possible to define more than one NUMA node per CPU socket (Intel Cluster-On-Die (COD) / sub-NUMA clustering technology). This scenario isn’t supported and can result in SAP HANA persistence corruptions (SAP Note 2116157).


2116157 - FAQ: SAP HANA Consistency Checks and Corruptions

"Unsupported activation of Intel Cluster-On-Die (COD) / sub-NUMA clustering technology"


Details:

Sub-NUMA Clustering by Frank Denneman


support Intel COD/SNC

SAP HANA News by XLC

SAP HANA NSE - a technical deepdive with Q&A
von Jens Gleichmann 6. Januar 2025
SAP NSE was introduced with HANA 2.0 SPS04 and based on a similar approach like data aging. Data aging based on a application level approach which has a side effect if you are using a lot of Z-coding. You have to use special BADI's to access the correct data. This means you have to adapt your coding if you are using it for Z-tables or using not SAP standard functions for accessing the data in your Z-coding. In this blog we will talk about the technical aspects in more detail.
The SAP Enterprise Cloud Services Private Cloud Customer Center (PC3) - a new digital delivery
von Jens Gleichmann 5. Januar 2025
The SAP Enterprise Cloud Services Private Cloud Customer Center (PC3) - a new digital delivery engagement model dedicated to manage service delivery for RISE with SAP S/4HANA Cloud, private edition customers.
Proactive maintenance for SAP RISE will start now in 2025
von Jens Gleichmann 5. Januar 2025
Proactive maintenance for SAP RISE will start now in 2025 with minor tasks like updating SPAM/SAINT and ST-PI / ST-A/PI. For those companies which are familiar with frequent maintenance windows, they are good to have such time frames to hold the systems up-to-date and secure. However, for larger companies where such frequent maintenance windows are not common because every minute of downtime is costly and may only really be necessary once, the situation is quite different.
Dynamic Aging for NSE - combined with Threshold and Interval option
von Jens Gleichmann 28. Dezember 2024
Dynamic Aging makes it possible to automatically manage at which point in time older partitions can be moved to the 'warm' data store. The data in a new OTHERS partition is 'hot' data, that is, stored in memory with the load-unit attribute implicitly set to COLUMN LOADABLE. As an extension of the Dynamic Range Partitioning feature Dynamic Aging makes it possible to automatically manage when older partitions can be moved to the 'warm' data store (Native Storage Extension) with the load-unit attribute for the partition set to PAGE LOADABLE. Warm data is then stored on disk and only loaded to memory when required. Dynamic Aging can be used with both THRESHOLD mode (defining a maximum row count number in partition OTHERS) and INTERVAL mode (defining a maximum time or other numeric interval between each new partition). For example, for a partitioned table which is managed by dynamic partitioning and containing date/time information, you can specify an age limit (for example six months) so that when data in an ol
automatic maintenance of the 'others' partition
von Jens Gleichmann 28. Dezember 2024
You can create partitions with a dynamic others partition by including the DYNAMIC keyword in the command when you create the partition, this can be used with either a THRESHOLD value to define a maximum row count number or an INTERVAL value which can be used to define a maximum time or other numeric 'distance' value. The partition can be either a single level or a second level RANGE partition and dynamic ranges can be used with both balanced and heterogeneous partitioning scenarios.
HANA Range Partitioning details
von Jens Gleichmann 23. Dezember 2024
For heterogeneous partitioning schemas Dynamic Range Partitioning is available to support the automatic maintenance of the 'others' partition. When you create an OTHERS partition there is a risk that over time it could overflow and require further maintenance. Using the dynamic range feature the others partition is monitored by a background job and will be automatically split into an additional range partition when it reaches a predefined size threshold. The background job also checks for empty partitions and if a range partition is found to be empty it is automatically merged to neighboring empty partitions (the others partition is never automatically deleted).
A success story regarding BW/4HANA and different data tiering and optimization methodes.
von Jens Gleichmann 20. Dezember 2024
A success story regarding BW/4HANA and different data tiering and optimization methodes. 1) Removed overhead in key attributes which reduced the PK size (often more than 50% of the overall table size) 2) optimized the partitioning design 3) used NSE for write optimized ADSOs 4) introduced NSE for several ADSOs 5) optimized usage of inverted individual indexes
ACDOCA table growth - how to handle it
von Jens Gleichmann 10. Dezember 2024
ACDOCA table growth - how to handle it in a S/4HANA system
HANA 2.0 SPS08 Roadmap
von Jens Gleichmann 6. Dezember 2024
SAP HANA 2.0 SPS08 Roadmap and features Q4 2024
Partitioning process
von Jens Gleichmann 26. November 2024
SAP HANA scaling and tuning with proper partitioning designs
more
Share by: