Oracle backup failing with status 6, RMAN error shows ORA-27206: requested file not found in media management catalog

Problem

Oracle backup is failing with status 6, the RMAN error shows ORA-27206: requested file not found in media management catalog.

Error Message

ORA-27206: requested file not found in media management catalog

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on c2 channel at 12/17/2010 13:52:32
ORA-19513: failed to identify sequential file
ORA-27206: requested file not found in media management catalog
ORA-19600: input file is backup piece  (+ORAFRA/oracle_client/backupset/2010_12_17/nnndf0_tag20101217t132820_0.3188.737991037)
ORA-19601: output file is backup piece  (bk_527_1_737991036)

Cause

The error is often caused by hostname resolution issues.

Solution

From the client, run the command:
/usr/openv/netbackup/bin/bpclntcmd -pn

This should return a response such as:

expecting response from server master_server_name
client_name   client_name   ip_address   port_number

For example:

# /usr/openv/netbackup/bin/bpclntcmd -pn
expecting response from server master_server.mydomain.com
oracle_client.mydomain.com 10.162.25.120 10.162.25.120 30105

The two client names must match exactly.  One of these names is returned from the gethostbyname lookup and the other is the client name defined in the policy.

1. Make sure that the master resolves to the same name that is in the policy attributes -- client name first.

2. Correct the client name in the policy from IP to the hostname of client.