ORA-16055: FAL Request Rejected

Question:  How can we solve this error that regularly comes up in the alertlog file of our primary database?

ora-19502 write error on file"",blockno(blocksize=)
ora-16055: FAL REQUEST REJECT
Arch: FAL Archive Failed,Archiver continuing.

Our database is 10g RAC with two nodes.

Answer:  To diagnose any error, you start by using the oerr utility to display the ORA-16055 error:

ORA-16055: FAL request rejected

Cause: FAL server rejects the FAL request from the FAL client. This may be caused by different reasons.

Action: To solve the problem.

As you can see, with this somewhat cryptic error message where the error may be "caused by different reasons," and the prescribed action is "to solve the problem," the key is to look at the error messages that came before and after the ORA-16055. 

In your case, there is an ORA-19502 error prior to the ORA-16055 with an Arch: FAL Archive Failed, Archiver continuing message following it. 

In many situations like this, the answer is that the archived log is not available for some reason, so the process can not see the file and cannot get it across to the standby site. It could be that the archived log was inadvertently removed when someone was trying to create some room in the file system, as is often the case with this unusual ORA-16055 error.

The key is to just insure logs are in the proper location, and if they are not, manually transport the files if possible or as needed.  For some versions and patchset levels of the Oracle RDBMS, FAL may just miss logfiles after a failover.  As noted in the text of the error summary, these problems may occur for any of several reasons, but the manual moving of the files to the expected location often provides a successful resolution of the ORA-16055.