Introduction

Recently i have talked to  my managers with this one big topic on my mind . The Linux department is rapidly patching their servers to higher levels of Linux and they ask for support during and after them patching the OS. From management side I needed clear directive  about Oracle team following those activities closely. With Oracle support  I have started to gather information about the should or should not  relink the software . Experience will tell which way was the right one.  Cause of course there is also risks involved when relinking the Oracle  software . Examples from past seem to tell that relink brought trouble with it too.

As a central note i was given  Mos Note Is It Necessary To Relink Oracle Following OS Upgrade? (Doc ID 444595.1)

In there you see two great references :

Note 883299.1 Oracle 11gR2 Relink New Feature

and

Note 220970.1 RAC: Frequently Asked Questions
Note 284785.1 How to Check Whether Oracle Binary/Instance is RAC Enabled and Relink Oracle Binary in RAC

From the rac note ) 220970.1  this is a interesting quote as with regard to  the Grid infra structure environment:

Do I need to relink the Oracle Clusterware / Grid Infrastructure home after an OS upgrade?

Using Oracle Clusterware 10g and 11.1, Oracle Clusterware binaries cannot be relinked. However, the client shared libraries, which are part of the home can be relinked, in most cases there should not be a need to relink them. See Note:743649.1 for more information. 
 
 Using Oracle Grid Infrastructure 11.2 and higher, there are some executables in the Grid home that can and should be relinked after an OS upgrade. The following steps describe how to relink an Oracle Grid Infrastructure for Clusters home: 
 
 As root:
 
 # cd Grid_home/crs/install
 # perl rootcrs.pl -unlock
 
 As the grid infrastructure for a cluster owner:
 
 $ export ORACLE_HOME=Grid_home
 $ Grid_home/bin/relink
 
 As root again:
 
 # cd Grid_home/crs/install
 # perl rootcrs.pl -patch 
 
 Note: If using Oracle Grid Infrastructure for Standalone Environments (Oracle Restart), see the Oracle Documentation for more information: http://docs.oracle.com/cd/E11882_01/install.112/e24321/oraclerestart.htm#BABJCHIJ

So should you relink ? Well frankly I would follow recommends  of Oracle in this matter  with the idea that it needs to be done on low priority boxes like test or preprod first before touching production . And should you decide not to relink due to experiences in the past , well i would recommend to be standby once the servers are patched Os wise and the grid infra structure  and databases are starting .

happy reading,

Mathijs