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Connecting to Oracle DB in NOMOUNT mode

  • June 2, 2025
  • 4 replies
  • 109 views

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Hello, we are trying to conduct an Non-RAC oracle duplicate operation and are having trouble getting the destination instance to a state other than unknown. The instance is started in NOMOUNT mode. For the connection string, we are using the sys account which has sysdba priveleges. For the Oracle User, we are using oracle. We have password file on the server, associated with the database and that the REMOTE_LOGIN_PASSWORDFILE is set to Exclusive. 

When doing a script preview, this error is listed:

Failed with Oracle DB/RMAN error [ORA-12528: TNS:listener: all appropriate instances are blocking new connections
RMAN-03002: failure of allocate command at 06/02/2025 11:25:32
RMAN-06171: not connected to target database

I am not the Oracle DBA, so what could I ask them to check for the connection issue?

Does the oracle user need something specific? 

How is the script connecting as sysdba without explicitly declaring in the connection string options?

Best answer by sbhatia

You can verify the following configurations for the RMAN duplication error (ORA-12528):

 

  • A static entry in listener.ora for the auxiliary instance (required for NOMOUNT state).
    • Listener restart after adding the entry.
  • Ask the DBA to test connectivity using SQL*Plus first:
    • sqlplus sys/<password>@<auxiliary_tns_entry> AS SYSDBA  

4 replies

CV_GK
Vaulter
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  • Vaulter
  • June 3, 2025

Hi ​@L. Bell 

What is the CV and DB version?

Please check if below oracle doc. link helps

https://support.oracle.com/knowledge/More%20Applications%20and%20Technologies/914099_1.html


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  • Author
  • Bit
  • June 3, 2025

CV 11.36.55, Oracle 19.3 on Redhat Enterprise 8.10


sbhatia
Vaulter
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  • Vaulter
  • Answer
  • June 3, 2025

You can verify the following configurations for the RMAN duplication error (ORA-12528):

 

  • A static entry in listener.ora for the auxiliary instance (required for NOMOUNT state).
    • Listener restart after adding the entry.
  • Ask the DBA to test connectivity using SQL*Plus first:
    • sqlplus sys/<password>@<auxiliary_tns_entry> AS SYSDBA  

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  • Author
  • Bit
  • June 3, 2025

Thank you ​@sbhatia.  The missing static entry was the issue.