Kamran Agayev's Oracle Blog

Oracle Certified Master

ORA-00304: requested INSTANCE_NUMBER is busy

Posted by Kamran Agayev A. on August 27th, 2015

There are a lot of explanation and different solutions for the error “ORA-00304: requested INSTANCE_NUMBER is busy”. But today, in my case while I was tyring to shutdown one of the cluster nodes, it hanged. There were no more information related with the hang in the log and trace files, so I went with shut abort and startup and got the following message:

SQL> startup

ORA-00304: requested INSTANCE_NUMBER is busy


The second node of the RAC database was up and running. And the instance_number was set to 2. After a little investigation, I found out that there was one process related with the database running on OS (even the database was closed) I killed that session and started the first node and it opened successfully

3 Responses to “ORA-00304: requested INSTANCE_NUMBER is busy”

  1. Arbind Karna Says:

    Hello Kamran,

    “There was one process related with the database running on OS”
    What command did you use to determine this? I too had the same issue where i had to reboot node.


  2. Kamran Agayev A. Says:


    Run “ps -ef | grep SID” where SID is your instance name
    Find that process and kill it with “kill -9 pid” command where pid is the id of that process

    Hope this help

  3. Arbind Karna Says:

    Thank You Kamran!

    – Arbind

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