In the world of the working Oracle DBA, it is possible one could be expected to manage dozens of production instances concurrently. Almost all working Oracle experts interact with their database with OS Commands, SQL*Plus scripts and shell scripts. The Oracle Enterprise Manager (OEM) GUI is primarily used only by the newbies and the more inexperienced DBAs.
OEM makes it easy for a neophyte to “pretend” to be an experienced DBA. Since it takes several years of full-time work to be familiar with the command-line syntax, OEM has been a great favorite among the “poser” crowd.
Anytime I work with a DBA who can only administer a database from OEM, I know that they are likely to belong to one of these groups:
Raw beginners - OEM is a great tool for beginners who have not yet learned that the command line interface is infinitely more flexible than the limited possibilities offered in OEM.
Posers - Fraudulent credentials and fake resumes are all too common in the Oracle industry, and reliance on GUI tools should be a tip-off that you are dealing with someone who has a very limited background in managing large computer systems.
Non-techies - Oracle managers with a non-technical background (no degree in Information Systems or Computer science) love to use OEM because it allows them to do tasks that would normally be far beyond their ability level.
A seasoned DBA knows that a firm knowledge of shell scripting, OS commands and and native SQL and DDL is indispensible for managing multiple instances.
Read more here about tips for managing a server with multiple instances without relying on OEM:
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Secrets for managing multiple instances
