Huge number of Oracle Database Home/Binary in a single server

Sometimes, during database consolidation planning, people tends to plan to install one ORACLE_HOME (DB Home/Binary) for each database.

Which means: Lets say, if there are 50 databases then there will be 50 ORACLE_HOME. Specially it's been seen in Exadata/SuperCluster which has capacity to consolidate a very large RDBMS environment.

Question is, is it really a good idea or crazy ?? !!!!

My understanding is very simple in this type of scenario. Lets say, there are 50+ Oracle Databases are planned to consolidate in an Exadata environment. In this case, it's always best to -

• Start with a minimum number of ORACLE_HOME (may be 2-4): The idea is to share a database home/binary  with all databases which are in the same version or patch level.
• Now, lets say, one database requires some specific sets of patches which are not at all related with the other databases. In that case the best option is to clone the exiting ORACLE_HOME to a new ORACLE_HOME, apply the required specific sets of patches, migrate/move the database into the new ORACLE_HOME.

This plan ensures availability of all the databases which are sharing a single ORACLE_HOME and keep the number of ORACLE_HOME at minimum.

Benefits

• Saves a lot of storage, lets say each ORACLE_HOME requires 10 GB space, so 50 ORACLE_HOME will requires 500 GB of space !!! Unnecessary waste of space.
• Saves a lot of man hour. Consider patching the same set of patches in 50 different ORACLE_HOME and troubleshoot if something goes wrong. Ohh, yes, it will definitely go wrong.