How to Clear RMAN Channel Configuration

I’m glad to get back to blog writing and, after a bit of a break, I’m starting with a brief post.

We DBAs have probably come across the RMAN (Recovery Manager) utility many times in our lives. We are also aware that existing configurations can be reverted using the “clear” option. However, while working in the RDBMS (Relational Database Management System) 19c version, I came across the following difference while clearing the channel configuration:

RMAN> show all;

RMAN configuration parameters for database with db_unique_name TEST are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 7;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/rman_bkp/bkp/test/rman/%F';
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT   '/rman_bkp/bkp/test/rman/%U';
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BZIP2'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/app/oracle/product/19.3.0/db_1/dbs/snapcf_test.f'; # default

RMAN> CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT CLEAR;

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01009: syntax error: found "clear": expecting one of: "double-quoted-string, equal, new, single-quoted-string"
RMAN-01007: at line 1 column 43 file: standard input

It’s clear that the straight usage of clear command doesn’t work. I noticed the removal of format clause from the syntax did the trick.

RMAN> CONFIGURE CHANNEL DEVICE TYPE DISK CLEAR;

old RMAN configuration parameters:
CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT   '/rman_bkp/bkp/test/rman/%U';
old RMAN configuration parameters are successfully deleted

RMAN> show all;

RMAN configuration parameters for database with db_unique_name TEST are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 7;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/rman_bkp/bkp/test/rman/%F';
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BZIP2'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/app/oracle/product/19.3.0/db_1/dbs/snapcf_test.f'; # default

I found this interesting, so I tested similar kinds of commands for ‘SBT_TAPE’ channels and found the following:

RMAN> CONFIGURE CHANNEL DEVICE TYPE SBT_TAPE PARMS 'NSR_ENV=(NSR_SERVER=**.**.com, NSR_DATA_VOLUME_POOL=**)';

new RMAN configuration parameters:
CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS  'NSR_ENV=(NSR_SERVER=**.**.com, NSR_DATA_VOLUME_POOL=**)';
new RMAN configuration parameters are successfully stored

RMAN> show all;

RMAN configuration parameters for database with db_unique_name TEST are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 7;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/rman_bkp/bkp/test/rman/%F';
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS  'NSR_ENV=(NSR_SERVER=**.**.com, NSR_DATA_VOLUME_POOL=**)';
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BZIP2'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/app/oracle/product/19.3.0/db_1/dbs/snapcf_test.f'; # default


RMAN> CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS CLEAR;

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01005: syntax error: found "clear": expecting one of: "double-quoted-string, equal, single-quoted-string"
RMAN-01007: at line 1 column 48 file: standard input

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01005: syntax error: found ";": expecting one of: "allocate, alter, backup, beginline, blockrecover, catalog, change, connect, copy, create, crosscheck, configure, duplicate, debug, delete, drop, exit, endinline, host, {, library, list, mount, open, print, quit, recover, register, release, replace, report, renormalize, reset, restore, resync, rman, run, rpctest, set, setlimit, sql, spool, startup, shutdown, send, show, test, upgrade, validate"
RMAN-01007: at line 1 column 53 file: standard input

RMAN> CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' CLEAR;

old RMAN configuration parameters:
CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS  'NSR_ENV=(NSR_SERVER=**.**.com, NSR_DATA_VOLUME_POOL=**)';
old RMAN configuration parameters are successfully deleted

RMAN> show all;

RMAN configuration parameters for database with db_unique_name TEST are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 7;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/rman_bkp/bkp/test/rman/%F';
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BZIP2'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/app/oracle/product/19.3.0/db_1/dbs/snapcf_test.f'; # default

We’re able to clear the current channel configuration by simply using the clear parameter value right after the configured channel name.

I hope you find this helpful. If you have any questions, or thoughts, please share them in the comments.