SAP Rolling Kernel Switch RKS
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The document provides guidelines for using the rolling kernel switch (RKS) to minimize downtime during kernel upgrades in high availability SAP NetWeaver systems, specifically for 72x releases. It details prerequisites and step-by-step procedures for executing RKS, including isolating instances and monitoring the process. The focus is on ensuring compatibility between old and new kernel versions and restoring normal operations post-upgrade.
SAP Rolling Kernel Switch RKS
- 1. SAP Rolling Kernel Switch
- 2. • The Rolling Kernel Switch (RKS) can be used to minimize the planned down;me in high availability systems in order to implement a new kernel patch level • This document focuses on the manual RKS available for 72x releases of SAP NetWeaver • The document is aimed at system administrators responsible for upgrading the kernel of SAP NetWeaver systems opera;ng the 721 kernel Introduc5on
- 3. • Applica;on severs of the system being patched must operate temporarily with a different kernel version • The kernel versions in ques;on must be compa;ble – i.e. the old kernel must be able to operate alongside the new kernel in the same SAP system • The system is a high availability system with clustered central services (SCS) and associated replicated enqueue managed by an enqueue replica;on server (ERS) Pre-‐Requisites
- 4. Prepara5ons • Download and extract the new kernel to your soPware repository • Prepare the SCS for RKS – copy the extracted “StoC.xml” file to the directory of the SCS instance denoted by system parameter $DIR_HOME • Use “sapcontrol -‐nr 00 -‐func;on ParameterValue DIR_HOME | tail -‐1” to determine this loca;on if you’re not sure • Physically switch in the new kernel by copying the newly prepared kernel into the /sapmnt/<SID> file system
- 5. Performing the RKS • RKS for each SAP instance comprises the following steps • Prepare the instance – Isolate the instance from any processing – Prevent direct logon, background processing, spooling etc. – Protect the transport system – adjust communica;on system in TMS • Restart the isolated instance – sapcpe will copy the new kernel from /sapmnt/<SID>/exe to the instance executable dircetory • Execute saproot.sh as root • Ac;vate the instance – Reverse all the isola;on steps above
- 6. Monitoring the RKS • The RKS can be monitored in SM51
- 7. • When all applica;on instances have been restarted, the dormant ERS should be restarted, the SCS cluster failed over and the remaining dormant ERS restarted Performing the RKS on SCS
- 8. Thank-‐you