Re: ORA-12521

From: Justin Mungal <>
Date: Thu, 23 Feb 2017 17:37:52 -0600
Message-ID: <>

I've seen that error intermittently occur when a device comes up with an IP address that's already in use by the cluster. You can check your switch ARP caches to see if multiple MAC addresses are claiming one of the IP addresses your app is trying to connect to.


On Thu, Feb 23, 2017 at 4:24 PM, Sanjay Mishra <> wrote:

> Has anyone experience ORA-12521 with RAC where everything is working fine
> from last several months but suddenly connection to one of 2-Node RAC is
> cauing failed to connect to specific instance. tnsnames.ora has
> Service_name as well as INSTANCE_NAME and they are same copied except
> INSTANCE_NAME is changed and one os working while other stopped working. It
> was working fine with no issue from long and suddenly started giving issue.
> If anyone can provide help as what else need to be checked is appreciated.
> I did the client trace and can see the one working fine is showing correct
> tns entry while other show Error-12521 as description.Nothing was changed
> on Database side
> Sanjay

Received on Fri Feb 24 2017 - 00:37:52 CET

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