# 15 – Evaluate tuning options for the operating system, database, and SAP application
**How do you understand and weigh the effects of different tuning options on your SAP system performance?** The great variance in performance recommendations for different combinations of SAP software offerings, supported operating systems and databases, and versions prohibit an exhaustive list of recommendations for performance excellence in a single document. With that in mind, the following guidance should be applicable to the majority of SAP use cases, and we will call out specific focus areas where applicable.
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/wellarchitected/latest/sap-lens/design-principle-15.html)
# Best Practice 15.1 – Follow operating system guidelines for SAP performance
SAP provides specific guidance on how best to tune for optimal performance for each of the operating systems that are supported for the SAP software you are deploying. Be sure to read all of the relevant SAP documentation on the operating system on which you are deploying both to understand the relevant tuning parameters and to take advantage of any operating system-specific options to make performance tuning easier and more dynamic.
**Suggestion 15.1.1 – Review operating system-related SAP notes prior to installation, version update, or infrastructure change**
When building or updating your operating system (through automation or manually) confirm that the appropriate performance settings specific to your combination of SAP software and operating system version are applied.
**Suggestion 15.1.2 – Evaluate operating system vendor-supplied SAP tuning**
Red Hat and SUSE provide images and repositories which contain tools and configuration optimized for running SAP. These are available in the AWS Marketplace or in a bring-your-own-subscription (BYOS) model.
Vendors are invested in ensuring that their operating systems are optimised for the SAP application. Using vendor-supplied tuning tools such as `saptune` or the (Ansible) system roles for Red Hat Enterprise Linux can assist in defining a known baseline for performance tuning. While this does not preclude tuning the operating system to best accommodate your specific SAP workload, these tools can reduce the effort associated with researching, calculating and applying the most common requirements. Configuration associated with the `tuned` daemon can also adjust dynamically using information it gathers from the system, including CPU count and available memory.
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/wellarchitected/latest/sap-lens/best-practice-15-1.html)
**Suggestion 15.1.3 – Apply relevant network parameters to the operating system**
SAP system performance can be seriously impacted by network misconfiguration, particularly in SAP HANA scale-out database designs as well as in communication between different application server instances and the database instance in a system environment. While in many cases in AWS, the maximum network throughput of an instance is dictated by the instance family and size, tuning of the network settings at the operating system level and in the SAP software itself can have an impact.
Refer to the following AWS and SAP recommendations:
+ AWS Documentation: [Benchmarking Network Throughput between Amazon EC2 Linux instances in the same Amazon VPC](https://aws.amazon.com/premiumsupport/knowledge-center/network-throughput-benchmark-linux-ec2/)
+ AWS Documentation: [Elastic Network Adapter – High Performance Network Interface for Amazon EC2](https://aws.amazon.com/blogs/aws/elastic-network-adapter-high-performance-network-interface-for-amazon-ec2/)
+ AWS Documentation: [Cluster Placement Groups](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html#placement-groups-cluster)
+ SAP Note: [2198693 - Key Monitoring Metrics for SAP on Amazon Web Services (AWS)](https://launchpad.support.sap.com/#/notes/2198693) [Requires SAP Portal Access]
+ SAP Note: [1612283 - Hardware Configuration Standards and Guidance](https://launchpad.support.sap.com/#/notes/1612283) [Requires SAP Portal Access]
+ SAP Note: [2081065 - Troubleshooting SAP HANA Network](https://launchpad.support.sap.com/#/notes/2081065) [Requires SAP Portal Access]
+ SAP Note: [1100926 - FAQ: Network performance](https://launchpad.support.sap.com/#/notes/1100926) [Requires SAP Portal Access]
# Best Practice 15.2 – Modify database parameters to align with hardware selection
SAP provides specific guidance to optimize performance of an SAP system by modifying certain parameters of the underlying database. These parameters are specific to database type and can vary based on whether it’s supporting an analytical or a transactional type application.
**Suggestion 15.2.1 – Review SAP HANA-specific tuning parameters, if applicable**
Operating System and SAP HANA Database parameters can significantly impact performance. Follow SAP on AWS recommendations for Operating system and storage configuration.
+ AWS Documentation: [SAP HANA on AWS – Operating System and Storage Configuration](https://docs.aws.amazon.com/sap/latest/sap-hana/operating-system-and-storage-configuration.html)
Refer to SAP notes and documentation for guidance on SAP HANA parameters including memory allocation.
+ SAP Note: [2000000 - FAQ: SAP HANA Performance Optimization](https://launchpad.support.sap.com/#/notes/2000000) [Requires SAP Portal Access]
+ SAP Documentation: [HANA Parameter: global\$1allocation\$1limit](https://help.sap.com/viewer/009e68bc5f3c440cb31823a3ec4bb95b/2.0.05/en-US/514ab38a2e574c85a70ebba80ff16d99.html#loio514ab38a2e574c85a70ebba80ff16d99__configSPS05_id_805)
+ SAP Note: [1999997 - FAQ: SAP HANA Memory](https://launchpad.support.sap.com/#/notes/1999997) [Requires SAP Portal Access]
+ SAP Note: [2926166 - How to limit the overall SAP HANA memory allocation](https://launchpad.support.sap.com/#/notes/2926166) [Requires SAP Portal Access]
**Suggestion 15.2.2 – Review database tuning guidance for non-SAP HANA databases**
Regardless of the underlying database for your SAP system, performance of the system is in part dependent on how the database is tuned. Each database has specific recommendations for tuning based on available compute, memory, and disk storage. Certain database parameters are dependent on your choice of underlying EC2 instance size; for example, the physical memory available will limit the `db_cache_size` for an Oracle database.
For information relevant to your database, refer to the following:
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/wellarchitected/latest/sap-lens/best-practice-15-2.html)
# Best Practice 15.3 – Modify SAP parameters to align with hardware selection
Tuning SAP application parameters can help improve the performance of the application. These parameters are often dependent on the underlying hardware configuration and operating system type.
** Suggestion 15.3.1 – Allow SAP to self-tune according to `PHYS_MEMSIZE` **
For recent versions of SAP software, using kernel release 7.40 or higher, self-tuning of certain parameters is possible and recommended. For instance, many parameters are derived via formulas related to the main memory available on an instance (PHYS\$1MEMSIZE). This allows for automatic tuning of memory parameters when resizing an EC2 instance underlying the SAP software to meet changing performance requirements.
+ SAP Documentation: [SAP Memory Management: Parameter Reference](https://help.sap.com/viewer/f146e75588924fa4987b6c8f1a7a8c7e/LATEST/en-US/493431b15cce5717e10000000a42189b.html)
+ SAP Note: [2085980 – New features in memory management as of Kernel Release 7.40](https://launchpad.support.sap.com/#/notes/2085980) [Requires SAP Portal Access]
**Suggestion 15.3.2 – Review SAP swap space and maximum memory use**
When running SAP on AWS, overutilized swap space on disk can cause I/O credit exhaustion on Amazon EBS and lead to performance degradation. Evaluate the different [EBS storage options](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-volume-types.html) available on AWS and configure swap space to meet your performance needs.
+ SAP Note: [1597355 - Swap-space recommendation for Linux](https://launchpad.support.sap.com/#/notes/1597355) [Requires SAP Portal Access]
+ SAP Documentation: [Swap Space Requirements](https://help.sap.com/saphelp_nw73/helpdata/en/49/325e42e93934ffe10000000a421937/frameset.htm)
# Best Practice 15.4 – Consider performance tuning for recovery and availability options
In alignment with both the Well-Architected Reliability and Operational Excellence pillars, tuning of the SAP system given your chosen recovery and resiliency requirements should be evaluated to minimize any performance impact. Take into consideration items such as system performance during a backup, clustering options for the chosen database (for example, synchronous vs. asynchronous SAP HANA System Replication), and the distribution of load across multiple SAP application server instances.
**Suggestion 15.4.1 – Review performance recommendations for backup and recovery solutions**
Each supported database has different recommendations to optimize the performance of backups and recovery operations, and these often work in conjunction with your chosen software solution for managing backups and restores, including third-party offerings.
In general, following the guidelines for improving throughput between an EC2 instance and the storage target of your backup (such as, EBS volumes, S3 buckets, and EFS file systems) can improve the performance of your backup and recovery.
For example, when using Amazon S3 as a repository for backups and AWS Backint Agent for SAP HANA, you can enable performance improvements via changing configuration parameters, such as the maximum concurrency settings. Another common way to improve backup performance is to increase EBS volume performance characteristics, such as maximizing GP3 throughput configuration to 1,000 MB/s.
For more information, refer to the following:
+ AWS Documentation: [AWS Backint Agent for SAP HANA](https://docs.aws.amazon.com/sap/latest/sap-hana/aws-backint-agent-installing-configuring.html#aws-backint-agent-performance-tuning)
+ AWS Documentation: [SAP NetWeaver on AWS – Backup and Recovery](https://docs.aws.amazon.com/sap/latest/sap-netweaver/backup-and-recovery.html)
+ AWS Documentation: [S3 Configuration Parameters](https://awscli.amazonaws.com/v2/documentation/api/latest/topic/s3-config.html)
+ SAP on AWS Blog: [Build for availability and reliability](https://aws.amazon.com/blogs/awsforsap/sap-on-aws-build-for-availability-and-reliability/)
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/wellarchitected/latest/sap-lens/best-practice-15-4.html)
**Suggestion 15.4.2 – Review configuration of clustering parameters**
Clustering options for SAP HANA and other databases often rely on a confirmed connection in a cluster (that is, a heartbeat) between the primary instance and the failover instance. SAP administrators must balance the speed with which an action can occur in the system with the potential for any failover side effects that may occur if there is a false negative interruption in communication. Follow recommendations for timeout parameters and related settings.
+ AWS Documentation: [SAP HANA on AWS: High Availability Configuration Guide for SLES and RHEL](https://docs.aws.amazon.com/sap/latest/sap-hana/sap-hana-on-aws-ha-configuration.html)
+ AWS Documentation: [SAP HANA on AWS Operations Guide: Networking](https://docs.aws.amazon.com/sap/latest/sap-hana/hana-ops-networking.html)
+ AWS Documentation: [SAP on AWS – IBM Db2 HADR with Pacemaker](https://docs.aws.amazon.com/sap/latest/sap-AnyDB/sap-ibm-pacemaker.html)
+ SAP Note: 1612105 - [DB6: FAQ on Db2 High Availability Disaster Recovery (HADR)](https://launchpad.support.sap.com/#/notes/1612105) [Requires SAP Portal Access]
+ Operating System-specific Documentation: [SUSE Linux SAP HSR Scale-up Performance Optimized Scenario](https://documentation.suse.com/sbp/all/html/SLES4SAP-hana-sr-guide-PerfOpt-12/index.html)
+ Operating System-specific Documentation: [Automated SAP HANA System Replication in Scale-Up in pacemaker cluster](https://access.redhat.com/articles/3004101)