Oracle Enterprise Manager and the 4K block size

  • From: Gus Spier <gus.spier@xxxxxxxxx>
  • To: oracle-l <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 30 Jul 2010 14:21:54 -0400

oracle rdbms
solaris 10

"Expediency is the enemy of integrity".  And the consequences of choosing
expediency apparently last forever.

So, in Bad Old Days, the previous incumbent selected a value for db_block_size
of 4096.  No doubt, that was the only value available to them at the time,
what and all with the pre-historic transition from Big Iron to

No one has seen a need to modify the db_block_size since those stirring

Now comes the New Guys ... who think they are going to do it better,
cheaper, faster, blah blah blah.  "We'll take advantage of modern tools,
like Oracle Enterprise Manager and Grid Control.  We'll let the service
center monitor the databases and free up numerours hours for REAL DBA work."

Have you ever tried to implement OEM on a database with a db_block_size of
4096?  When you have finally finished beating your head against the wall,
you read the message, " db_block_size must be at least 8192 "

OK, not a problem.  We know we cannot simply issue an "ALTER SYSTEM ..."
command and expect it to work.  We'll practice with Data Pump and export the
entire database; change the database parameter to 4096; and perform the

Well, maybe not ...

Now our latest theory is:

   1. New initSID.ora with the target db_block_size set to 8192
   2. Export the source db
   3. start up the *new db* with new initSID.ora
   4. Import the source database from the .dmp files

Then someone objects, "Wait a minute, did he say 'New DB?!'  No way.  We'd
have to change hard-coded references  that have been growing like Topsy
since 1995!  We'll have days and weeks of downtime!"

So, before I shrug off this latest disappointment and go back to wading
through four levels on indirection worth of shell scripts ... I remember
that OEM was owner by SYSMAN ... and I think I remember that SYSMAN had a
default tablespace of SYSAUX ... Does that mean I might be able to make a
SYSAUX tablespace with a default block size of 8k and fool the OU Installer
into letting me make progress?

Does anybody know?



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