Tag Archives: oem12c

RAC One Node on Oracle Enterprise Manager 12c

One of the promises from Oracle for OEM 12c was improved support for Oracle RAC One Node. I have spent quite a bit of time researching RON, and wrote a little article in 2 parts about it which you can find here:

One of my complaints with it was the limited support in OEM 11.1. At the time I was on a major consolidation project, which would have used OEM for management of the database.

OEM 11.1

Unfortunately OEM 11.1 didn’t have support for RAC One Node. Why? RON is a cluster database running on just one node. The interesting bit is that the ORACLE_SID is your normal ORACLE_SID with an underscore and a number. Under normal circumstances that number is _1, or RON_1. But as soon as you relocate the database using srvctl relocate database -d a second instance RON_2 is started until all sessions have failed over.

OEM obviously doesn’t know about RON_2: it was never discovered. Furthermore, the strict mapping of instance name to host is no longer true (the same applies for policy managed databases by the way!). A few weeks and a few switchover operations later you could be running RON_2 on racnode1.

As a consequence, the poor on-call DBA is paged about a database that has gone down, when it hasn’t-it’s up and running. As a DBA, I wouldn’t want that. After discussions with Oracle they promised to fix that problem, but it hasn’t made it into 11.1 hence this blog post about 12.

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