•
The
RMAN command output contains actions that are relevant to the RMAN job as well
as error messages that are generated by RMAN, the server, and the media vendor.
RMAN error messages have an RMAN-nnnn prefix. The output is displayed to the
terminal (standard output) but can be written to a file by defining the LOG
option or by shell redirection.
•
The
RMAN trace file contains the DEBUG output and is used only when the TRACE
command option is used.
•
The
alert log contains a chronological log of errors, nondefault initialization
parameter settings, and administration operations. Because it records values
for overwritten control file records, it can be useful for RMAN maintenance
when operating without a recovery catalog.
•
The
Oracle trace file contains detailed output that is generated by Oracle server
processes. This file is created when an ORA-600 or ORA-3113 (following an
ORA-7445) error message occurs, whenever RMAN cannot allocate a channel, and
when the Media Management Library fails to load. It can be found in
USER_DUMP_DEST.
•
The
sbtio.log file contains vendor-specific information that is written by the
media management software and can be found in USER_DUMP_DEST. Note that this
log does not contain Oracle server or RMAN errors.
Using
the DEBUG Option
•
The
DEBUG option is used to:
•
View
the PL/SQL that is generated
•
Determine
precisely where an RMAN command is hanging or faulting
•
The
DEBUG option is specified at the RMAN prompt or within a run block.
•
The
DEBUG option creates an enormous amount of output, so redirect the output to a
trace file:
$
rman target / catalog rman/rman debug
trace trace.log
•
The
DEBUG option displays all SQL statements that are executed during RMAN
compilations and the results of these executions. Any information that is
generated by the recovery catalog PL/SQL packages is also displayed. In the
following example, the DEBUG output is written during the backup of data file
3, but not data file 4:
RMAN> run {
debug on;
allocate channel c1 type disk;
backup datafile 3;
debug off;
backup datafile 4; }
•
Remember
that the DEBUG output can be voluminous, so make sure that you have adequate
disk space for the trace file. This simple backup session that does not
generate any errors creates a trace file that is almost half a megabyte in
size:
•
$ rman target
/ catalog rman/rman debug trace sample.log
•
RMAN>
backup database;
•
RMAN> host
"ls –l sample.log";
Interpreting
RMAN Error Stacks
Because of
the amount of data that RMAN logs, you may find it difficult to identify the
useful messages in the RMAN error stack. Note the following tips and
suggestions:
•
Because
many of the messages in the error stack are not meaningful for troubleshooting,
try to identify the one or two errors that are most important.
•
Check
for a line that says Additional information followed by an integer. This line
indicates a media management error. The integer that follows refers to code
that is explained in the text of the error message.
•
Read
the messages from bottom to top because this is the order in which RMAN issues
the messages. The last one or two errors that are displayed in the stack are
often informative.
•
Look
for the RMAN-03002 or RMAN-03009 message immediately following the banner. The
RMAN-03009 is the same as RMAN-03002 but includes the channel ID. If the
failure is related to an RMAN command, then these messages indicate which
command failed. The syntax errors generate an RMAN-00558 error.
