Guest Author: Nick Quarmby
This is the second in a series of articles about common technical myths or misunderstandings about the E-Business Suite. Other articles have covered installations, patching, migrations, upgrades, and maintenance. This article discusses cloning. Subsequent articles will cover patching, migrating, upgrading, and general maintenance.
Each article is absolutely not definitive and I’d be interested in comments from readers who think there are other misconceptions about the day-to-day maintenance and upgrade of a typical E-Business Suite environment.
COMMON ERROR #1: Assuming that use of the Rapid Clone utility is optional when cloning your Apps environment.
ORACLE’S RECOMMENDATION: Rapid Clone greatly simplifies the process of cloning your E-Business Suite environment. Simply copying your E-Business Suite environment to new host machines, editing the context files to reflect the new environment and then running AutoConfig is not a supported cloning method. Devising your own cloning methodology that bypasses Rapid Clone is a dangerous strategy. If Rapid Clone does not work for you, then raise a Service Request and ask for help in fixing the issue. Do not create an alternative cloning method that you hope will sidestep whatever issue you are seeing.
COMMON ERROR #2: Assuming that the preclone scripts only need to be run once on an environment.
ORACLE’S RECOMMENDATION: You must run the preclone scripts immediately before each clone, prior to shutting down the application and database tiers in order to copy the files for cloning (or RMAN backup). It’s also good practice to remove or rename the database tier $ORACLE_HOME/appsutil/clone and application tier $COMMON_TOP/clone before running the preclone script. Always check the cloning documentation for the latest patches before each clone.
COMMON ERROR #3: Mistakenly using Rapid Clone to migrate from 32 bit Linux to 64 bit Linux.
ORACLE’S RECOMMENDATION: Although these platforms are binary compatible, cloning your E-Business Suite from 32 bit Linux to 64 bit Linux will only produce a 32 bit E-Business Suite environment on your 64 bit operating system. In order to fully exploit your 64 bit operating system you should follow specific migration documentation for your E-Business Suite environment. The same applies to other certified operating systems available as both 32 and 64 bit.
COMMON ERROR #4: Mistakingly forgetting to update the central inventory when overwriting a previous clone with a new clone in the same location.
ORACLE’S RECOMMENDATION: If you regularly repeat a clone to the same location on a target node, you must ensure the central inventory entries for the previous clone are removed before configuring the new clone. As with a repeated installation, when deleting an E-Business Suite environment prior to cloning to the same location, in addition to shutting down and deleting files, you must also remove its entries from the central inventory. The central inventory is a file based repository of all Oracle homes installed on a node. This central inventory may exist outside the E-Business Suite file system and is not always removed when you remove the E-Business Suite file system. If the central inventory contains entries for previously deleted E-Business Suite environments then subsequent new clones may fail.
COMMON ERROR #5: Assuming that the clone is not a completely accurate copy.
ORACLE’S RECOMMENDATION: A system created using Rapid Clone is the most genuine and supported copy you can create. It has an identical database, application tier and technology stack as the source environment it was created from. The only significant difference between a source and target clone environment is the data specific to the new hardware (node names, directory locations etc.). It is supported to clone your production environment, apply patches to the clone and then clone the patched system back to become your new production environment. Assuming the cloning documentation is followed correctly, an E-Business Suite environment does not degrade through being repeatedly cloned. References