Installation guide

6.2.2 SAP Virtual IP Addresses
SAP NetWeaver is typically installed via the graphical installation tool sapinst. Before
beginning the installation, determine which IP addresses and host names are preferred for
use during the SAP installation. First, each node requires a static IP address and an
associated host name. This address is also referred to as the physical IP address . Second,
each database and SAP instance will require a virtual IP address / host name. The virtual
addresses must not be configured at the operating system level because they are under the
control of RHCS. Those addresses are referred to as the virtual IP addresses.
Local dialog instances, which are not part of the cluster, use a virtual host name as an alias to
the physical host name so those SAP instances are not failed over by RHCS.
The enqueue replication instances do not need IP addresses because no connections are
established with them. The virtual host name is only used to start the instances manually via
the sapstart command and to distinguish their profile names from physical host names.
Edit the /etc/hosts file on all nodes and add the virtual host names and their associated IP
addresses. Additionally, add any other cluster relevant host name and address (e.g., the
physical host names or addresses of the nodes) to /etc/hosts so that the DNS server is no
longer a single point of failure.
6.2.3 SAP File Systems
The file systems for our scenario must be prepared before installing SAP NetWeaver.
File systems must be set up locally, on shared storage with file system type GFS, and on a
highly available NFS server.
6.2.3.1 Local File Systems
Directories such as /usr/sap and /sapmnt can be created locally.
The directory /usr/sap/tmp should also be locally.
6.2.3.2 Shared Storage File Systems
By using GFS as file system for SAP and database instances, the directory /usr/sap/<SID>
and any lower directory can be a GFS mount point.
The database directories can also reside entirely on GFS. Follow the database file system
setup recommendations from the SAP installation guide. It is recommended to have different
physical mount points for specific directories.
The GFS mounts from shared storage must be added to /etc/fstab so they get mounted at
system boot.
6.2.3.3 NFS Mounted File Systems
The /sapmnt/<SID> file system should resist on a high available NFS to be available for
additional application server outside the cluster.
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