Prepare your Linux for your SAP solution with saptune

Prepare your Linux for your SAP solution with saptune

First of all for what do you need the tool saptune?

automatically tuning your system without reading tons of SAP notes
ensures that all your SAP systems configured identically with a central solution
create your own customized profiles

Why you have to configure all this parameters?

ensure system performance for your SAP solution like HANA
run a stable system
ensure SAP support for certified solution like HANA

SLES for SAP Applications 12 SP2 now ships with the system tuning utility saptune.
In addition to saptune, the package sapconf contains the basic utility sapconf. sapconf also allows tuning for SAP systems but is less comprehensive and offers less granularity than saptune. However, unlike saptune, sapconf is available directly in SUSE Linux Enterprise Server and thus not dependent on using SLES for SAP.

sapconf and saptune both rely on the daemon tuned to set tuning configuration but they use different (though at times very similar) tuning profiles. Therefore, only one of sapconf or saptune can be enabled at a time.

If you have installed your SLES system with the SAP installation wizard the correct profile is already used.

So we have two tools sapconf and saptune:
sapconf: available in SLES11 and SLES12 (without SLES for SAP Applications subscription)
saptune: available since SLES12 SP2 (only with SLES for SAP Applications subscription)

more details about the older tool sapconf in Ulrich Schairer’s blog

How to activate it?

1.List available solutions

saptune solution list

tuned-adm list

2. Choose a solution

saptune solution apply SOLUTION

tuned-adm PROFILENAME

3) start daemon

saptune daemon start

disable / enable daemon

systemctl disable tuned
systemctl enable tuned

4) check active profile

active profile can be found under
/etc/tuned/active_profile
or

tuned-adm active
tuned-adm list

5) Apply single SAP notes

saptune note list

You can apply, simulate, verify, customise and revert such notes.

6) Switch between profiles

tuned-adm PROFILENAME

7) Customize a existing SUSE standard profile

2205917 – SAP HANA DB: Recommended OS settings for SLES 12 / SLES for SAP Applications 12

SAP recommendation

cat /usr/lib/tuned/sap-hana/tuned.conf

=> ‘force_latency’ is already set

If you want to add sysctl kernel parameter from other vendors (e.g. VMware for virtualization or NetApp for storage), you can set them in your own profile. Just look into their best practise guides for the recommended parameters.

Example:

net.ipv4.tcp_slow_start_after_idle=0

cp /usr/lib/tuned/sap-hana/tuned.conf /etc/tuned/sap-hana/tuned.conf
vi /etc/tuned/sap-hana/tuned.conf

[sysctl]
net.ipv4.tcp_slow_start_after_idle = 0

[bootloader]
cmdline = YOUR_ADDITIONAL_KERNEL_PARAMETERS

[script]
script = /usr/lib/tuned/sap-hana/script.sh

8. Create your own profile

cp /usr/lib/tuned/sap-hana/tuned.conf /etc/tuned/sap-cust/tuned.conf

[sysctl]
parameter = value
[script]
script = /usr/lib/tuned/sap-hana/script.sh

adjust the parameters for your needs – ‘sap-cust’ is the name of the new profile

tuned-adm list

=> you can see two new profiles ‘sap-test’ and ‘sap-cust’

Logfiles:

/var/log/sapconf.log
/var/log/tuned/tuned.log

Details

Delivered SAP Notes

/etc/sysconfig/sap*

Standard Tuned files

/usr/lib/tuned

Important notes

2382421 Optimizing the Network Configuration on HANA- and OS-Level
1868829 Startup Issues Because Number of Active I/O Requests to Queue Exceeds aio-max-nr Limit
2205917 SAP HANA DB: Recommended OS settings for SLES 12 / SLES for SAP Applications 12

Documentation

SLES for SAP 12 SP3

Source: https://blogs.sap.com/2017/12/22/prepare-your-linux-for-your-sap-solution-with-saptune/