FS_CLONE Phase - R12.2 Online Patching Cycle

-It is a stand-alone command used for filesystem cloning.
-Standard cloning (using adcfgclone.pl) cannot be used to synchronize the run and patch file systems.
-This special phase must be run from the run file system, and cannot be specified with any other phase.
-It should be before the next prepare phase is run.
-It is an alternate to PREPARE phase

FS_CLONE Phase - alternate to PREPARE phase ?

-Create a new patch file system by cloning the run file system.
-This method is useful if the APPL_TOPs have become very unsynchronized (meaning that there would be a large number of delta patches to apply).
-It is a heavyweight process, taking a backup of the entire current patch APPL_TOP and then cloning the run APPL_TOP to create a new patch APPL_TOP.
-A total of least 75 GB of free disk space is required. Also, you will need at least 25 GB of free space in your temporary directory (typically /tmp).
-As well as being resource-intensive, this method is very time-consuming and requires several manual actions by the user.
-It should therefore be used only when necessary.

FS_CLONE Phase – Possible Scenarios

Instance is 12.2.1 and we want to upgrade to 12.2.2

Method 1 : adop phase=prepare + adop phase=apply
adop phase=prepare
adop phase=apply patches=16207672

Start time : Nov 14 2013 08:41:29 End time : Nov 14 2013 16:47:08
Total Time : approximately 8 hours

adop phase=finalize
waiting for downtime approval from customer
adop phase=cutover ( 1 hour downtime )
Released the instance to customer
adop phase=cleanup

Method 2 : adop phase=fs_clone + adop phase=prepare

Here fs_clone phase will take 2 hours 36 Minutes

Start Time : Nov 16 2013 22:06:44 End Time : Nov 17 2013 00:43:29 Total Time : 2 hours 36 Minutes
prepare phase will take 16 Minutes
Start Time : Nov 17 2013 00:44:31 End Time : Nov 17 2013 01:01:01 Total Time : 16 Minutes
It takes approximately 3 hours

Conclusion :

Method 1 takes 8 hours but consumes less resource and less complexity.
Method 2 takes 3 hours and consumes more resource and more complexity.