SLES 11 SP4 is supported:
https://www.suse.com/products/sles-for-sap/technical-information/
https://www.suse.com/products/sles-for-sap/resource-library/
Release notes for SLES 11 SP4.
https://www.suse.com/releasenotes/x86_64/SUSE-SLES/11-SP4/
If you use SLES for SAP applications, the kernel is already optimized with relevant parameters.
Also check SUSE documentation and SAP Note
https://www.suse.com/documentation/sles_for_sap/sles_for_sap_guide/data/s4s_configuration.html
https://websmp230.sap-ag.de/sap/support/notes/1557506