In an attempt to reduce the complexity of a solution, I've been asked to convert a two node Oracle 10g RAC production database to single instance. The database is running on RHEL5 with ASM on SAN.

I imagine at least the following steps will be required:

  • Remove the instances from cluster ready services
  • Restrict the second node's access to shared storage
  • Remove redo logs for second instance
  • Drop undo tablespace for second instance
  • Remove references to second instance from the pfile/spfile
  • Relink the Oracle binaries, refer to post from Gaius

Any other considerations? Might it be better to create a single node physical standby?

Does anyone know of a related whitepaper or metalink note?

  • what is the "original question"? you should link to the original question. – J-16 SDiZ Nov 8 '10 at 11:33
  • The original question? I'm not sure I understand what you're asking. – Roy Nov 8 '10 at 13:10

Does this link helps?

For ASM, edit the ASM pfile and remove these lines


You may also found metalink 239998.1 helpful if rootdelete.sh fails.

  • Yes it does, thank you. Although, I'm wondering if there might be some special considerations with regards to ASM. – Roy Nov 8 '10 at 13:12
  • updated for asm – J-16 SDiZ Nov 9 '10 at 0:14

You will also need to relink the Oracle binaries:

$ cd $ORACLE_HOME/rdbms/lib
$ make -f ins_rdbms.mk rac_off
$ make -f ins_rdbms.mk ioracle

Of course, if you create a single-node standby it will already be "un-RAC'd" but you will still need to "clean up" the second redo thread etc. Just had a quick look on Metalink and their search engine finds lots of results converting from single instance to RAC but I don't think Oracle wants you to do it the other way 'round...

  • Good point, thanks. I've updated the original post. – Roy Nov 8 '10 at 10:53

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