Discrepancies in Oracle 11gR2 grid infrastructure install guide for Linux:

- Oracle instructs you to create VIP's on both nodes as a preinstall task.
However, if you do so, Oracle grid infrastructure installer will tell you the VIP adresses are already in use.

- Even though you have set up passwordless ssh connectivity between two RAC nodes, the installer keeps telling you this is not the case. I guess it has something to do with Oracle using rsa1. I gave up and gave both my oracle users the same password, and clicked on "setup", and let the installer do it for me. Everything went fine afterwards.

- /usr/sbin/oracleasm enable and disable have been deprecated on RHEL 5.3.
You have to use chckconfig oracleasm on.
If you fail to do so, upon reboot, asmlib is not loaded, and your voting disks and OCR are corrupted.

- If you use ACFS have to use different ORACLE_BASE directories for the Oracle grid infrastructure user (ex:grid: /u01/app/grid/), and the Oracle database user (ex: oracle: /u01/app/oracle/).
In the install doc, this is not so clear, as only ORACLE_HOME directories (ex:/u01/app/11.2.0/grid/ for grid and /u01/app/oracle/acfsmounts/orahome1/ for oracle) have to be different, the ORACLE_BASE seeming to be a unique one.

- Even though you can set up a shared ORACLE_HOME through ACFS for the database binaries, you still have to rely on ocfs2 if you want to have the Oracle grid infrastructure binaries on a shared filesystem.

- You absolutely have to be patient ant wait for the root.sh script to finish on your first node (can last half an hour), before you may execute it on your other nodes. Else, your  installation will miserably fail.

A complete RAC installation guide for Oracle 11gR2 on RHEL 5.3 with multipath will follow soon.