Recommended SUSE SLES 4 SAP Settings
This document (7024082) is provided subject to the disclaimer at the end of this document.
SUSE Linux Enterprise Server 15 for SAP Applications SP1
1) the I/O Scheduler
The I/O Scheduler is responsible for the I/O Delivery to the back-end.
The Default on SUSE Linux Enterprise Server 12 and SUSE Linux Enterprise Server 15 SP1 is cfq.
For most SAP environments (e.g. RAID, storage arrays, virtualization) the IO scheduler 'noop' (non-multiqueue) or 'none' (multiqueue) is the better choice.
To set the scheduler, the recommendation is to use sapconf or saptune.
Recent versions of sapconf and saptune support both schedulers by default and will set either "noop" or "none" as default.
Please test the impact of the available schedulers and choose the most effective one.
This is also mentioned in SAP Notes 1984787 1680803 2161991
More information can also be found:
2) dirty_bytesThe Dirty Bytes are a Threshold Setting. It comes in different Flavours, as a Ratio or Direct Byte Value. Once this defined Threshold is reached, the Kernel will write out all the Dirty Bytes in one go.
It is recommended to set the Dirty Bytes, and to set them low, for example to
vm.dirty_background_bytes = 314572800vm.dirty_bytes = 629145600
beginning on any Machine with more than 8GB of Memory.
3) transparent_hugepagesThe Transparent Hugepages should always be disabled. Either as Kernel Command line
or online without Reboot
echo never >/sys/kernel/mm/transparent_hugepage/enabled
This is mentioned in SAP Note 2205917.
This is mentioned in SAP Note 2205917.
5) pagecache_limit_mbThe pagecache_limit_mb is a special enhancement from SUSE and will limit the Pagecache.
This setting can be beneficial, but has to be set to the right value, or should be turned off. So it has either be set it to the correct value, which can be found in SAP Note 1557506 - Linux paging improvements, or set to 0.
saptune is installed via zypper :
zypper in saptune
It should be ensured that the version being installed is >= 2.0.1
benromach:~ # rpm -q saptune
It could be checked for a complete solution, for this example HANA is used
benromach:~ # saptune solution list
All solutions (* denotes enabled solution, O denotes override file exists for solution, D denotes deprecated solutions):
BOBJ - 941735 1771258 1984787 SAP_BOBJ
HANA - 941735 1771258 1980196 1984787 2205917 2382421 2534844
D MAXDB - 941735 1771258 1984787
NETWEAVER - 941735 1771258 1984787
NETWEAVER+HANA - 941735 1771258 1980196 1984787 2205917 2382421 2534844
S4HANA-APP+DB - 941735 1771258 1980196 1984787 2205917 2382421 2534844
S4HANA-APPSERVER - 941735 1771258 1984787
S4HANA-DBSERVER - 941735 1771258 1980196 1984787 2205917 2382421 2534844
SAP-ASE - 941735 1410736 1680803 1771258 1984787
benromach:~ # saptune note customise 1557506
benromach:~ # saptune note customise 1984787
benromach:~ # saptune solution apply HANA
WARNING: [block] section detected: Traversing all block devices can take a considerable amount of time.
WARNING: Be aware: system-wide UserTasksMax is now set to infinity according to SAP recommendations.
This opens up entire system to fork-bomb style attacks.
WARNING: System does not support Intel's performance bias setting
WARNING: governor settings not supported by the system
WARNING: latency settings not supported by the system
All tuning options for the SAP solution have been applied successfully.
it can be checked at a later time what tuning is applied with a simple command :
benromach:~ # saptune note list
current order of applied notes is: 941735 1771258 1980196 1984787 2205917 2382421 2534844
to add the pagecache_limit_mb a single note can be applied with the command :
benromach:/ # saptune note apply 1557506
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- Document ID:7024082
- Creation Date: 22-Aug-2019
- Modified Date:05-Aug-2020
- SUSE Linux Enterprise Server for SAP Applications
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