User's Guide

Directory Structure Configuration
This section adds implementation practices to the architectural decisions made in the chapter "Storage Layout
Considerations". If layout option 1 or option 2 is used, then the non-CFS directory structure conversion must
be performed. An implementation based on HP LVM is described in this document. VxVM can similarly be
used. Option 3 maps to the CFS configuration for SAP. In this case, usage of VxVM and CVM are mandatory.
Cluster Filesystem Configuration
Logon as root to the system where the SAP Central Instance is installed. If the database is installed on a
different host, also open a shell as root on the database machine. Make sure that all SAP instances and the
database got stopped manually.
NOTE: These steps are only required if HP Serviceguard Cluster File System is going to be used for the
SAP instances.
Installation Step: IS009
Verify that the existing disk group layout is compliant with the needs of the Serviceguard package(s) as
specified in the tables for option 3 of Chapter 2.
All directories that are labeled shared in these tables need to reside on logical volumes on a shared external
storage system. The volume management needs to be VxVM based. The volumes can be converted using
vxvmconvert(1m), if the SAP System got originally installed on HP LVM volumes instead.
All SAP Instances (CI, SCS, ASCS, D,...) must have instance numbers that are unique for the whole cluster.
Exceptions are (A)REP instances that follow an old naming convention of sharing the instance ID with their
corresponding (A)SCS instance. This naming convention should no longer be used, since it cannot be
combined with the SAP startup framework. For a clustered instance with instance number <INSTNR> execute
the command:
ls -d /usr/sap/???/*<INSTNR>
It should not reply any match on any node. Otherwise refer to the SAP documentation how to change instance
IDs for the relevant instance type. It might be simpler to reinstall one of the conflicting instances.
Installation Step: IS030
Comment out the references to any file system that classified as a shared directory in Chapter 2 from the
/etc/fstab .
Also make sure that there are no remaining entries for file systems converted in IS009.
MAXDB Database Step: SD040
This step can be skipped for MAXDB instances starting with versions 7.6.
MAXDB is not supported on CFS, but can be combined with SAP instances that use CFS. In this case, make
sure you have mounted a sharable logical volume on /sapdb/<DBSID>/wrk as discussed in section
MAXDB Storage Considerations in Chapter 2.
NOTE: dbmcli commands only work for users that have correct XUSER settings in place.
Change the path of the runtime directory of the MAXDB and move the files to the new logical volume
accordingly.
cd /sapdb/data/wrk/<DBSID>
find . -depth -print | cpio -pd /sapdb/<DBSID>/wrk
cd ..
rm -r /sapdb/data/wrk/<DBSID>
dbmcli -d <DBSID> -u control,control
...> db_cold
46 Step-by-Step Cluster Conversion