Plan Your SAP Configuration

*IMPORTANT: In keeping with industry best practices and announced with the release of v9.6.2, beginning with v9.7.0 SIOS will no longer support new or existing configurations with NFS servers/clients on the same nodes as the SAP services when setting up an SAP system (also known as “loopback configuration”).  Instead, we require using alternate configurations such as:
• EFS in AWS
• Azure Premium File Shares with NFS
• Google NFS Share
• NFS as separate cluster

1. Determine which configuration you wish to use. The required tasks vary depending on the configuration.

2. The SAP system wide /usr/sap/trans directory must be hosted by a file server that is NFS shared and fully accessible. A separate LifeKeeper NFS cluster will provide highly available NFS resources.

3. Consider the storage requirements for SAP and DB as listed in the SAP Installation Guide. Most of the SAP files will have to be installed on shared storage. Consult the LifeKeeper for Linux Technical Documentation for the database-specific recovery kit for information on which database files are installed on shared storage and which are installed locally. Note that in an SAP environment, SAP requires local access to the database binaries, so they will have to be installed locally. Determine how to best use your shared storage to meet these requirements.

Also note that when shared storage resources are under LifeKeeper protection, they can only be accessed by one server at a time. If the shared device is a disk array, an entire LUN is protected. If a shared device is a disk, then the entire disk is protected. All file systems located on a single volume will therefore be controlled by LifeKeeper together. This means that you must have at least two logical volumes (LUNs), one for the database and one for SAP.

4. Virtual host names will be needed in order to identify your systems for failover. A new IP address is required for each virtual host name used. Make sure that the virtual host name can be correctly resolved in your Domain Name System (DNS) setup, then proceed as follows:

a. Create the new virtual ip addresses by using the command:

ip addr add {IPADDRESS}/{NETMASK} dev eth0 (use the right netmask for your configuration)

Note: To verify these new virtual ip addresses use the ip addr show command.

b. A separate virtual IP will also be needed for the ERS instance if using ERSv2.

In order to associate the switchable IP addresses with the virtual server name, edit /etc/hosts and add the new virtual ip addresses.

Note: This step is optional if the Primary Application Server and the Database are always running on the same server and communication between them is always local. But it is advisable to have separate switchable IP addresses and virtual server names for the Primary Application Server and the Database in case you ever want to run them on different servers and associated virtual hostnames.

5. Stop the caching daemon on both machines.

rcnscd stop

6. Mount the software.

mount //{path of software} (no password needed)

7. Run an X session (either an ssh -X or a VNC session — for Microsoft Windows users, Hummingbird Exceed X Windows can be used).

Note: When sapinst is run, the directory will be extracted under /tmp

8. When installing SAP (specifically ASCS or SCS) you need to specify the SAPINST_USE_HOSTNAME={virtual hostname} option. This is also required for the ERS instance if using ERSv2, but not if using ERSv1.

Note: Specify sapinst SAPINST_USE_HOSTNAME={virtual hostname} where virtual hostname is the hostname that resolves to the virtual IP that will float between the nodes.

Important Note

The LifeKeeper SAP Recovery Kit relies on the SAP Host Agent being installed. If this software is not installed, then the LifeKeeper SAP Recovery Kit will not install. With SAP Netweaver version 7.3 and higher, this host agent is supplied; however, prior versions require a download from SAP. It is recommended that you consult your SAP help notes for your specific version. You can also refer to the Help Forum (help.sap.com) for further documentation.

• The saphostexec module, either in RPM or SAR format, can be downloaded from SAP.

• To make sure that the modules are installed properly, there are a few modules to search for (saposcol, saphostexec, saphostctrl). These modules are typically found where SAP is installed (typically /usr/sap directory).