My one of the client database backup have been failed since one week due to “RMAN-06183 datafile or datafile copy /vcboradata/oradata/datafile/system01.dbf (file number 1) larger than MAXSETSIZE”. Error itself is pretty explanatory. The size of the system01.dbf datafile had exceeded the RMAN parameter MAXSETSIZE, i.e. 15G

Error log:
RMAN>
Starting backup at 2016-11-03 10:41:39
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=1008 device type=DISK
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
channel ORA_DISK_1: starting piece 1 at 2016-11-03 10:41:41
channel ORA_DISK_1: finished piece 1 at 2016-11-03 10:41:43
piece handle=/cbsrmanbackup/rman/VCBCBS/backupset/2016_11_03/o1_mf_ncnnf_TAG20161103T104140_d1okrg13_.bkp tag=TAG20161103T104140 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02
Finished backup at 2016-11-03 10:41:43
Starting Control File and SPFILE Autobackup at 2016-11-03 10:41:43
piece handle=/cbsrmanbackup/rman/VCBCBS/autobackup/2016_11_03/o1_mf_s_926937704_d1okrjqq_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 2016-11-03 10:41:45
Starting backup at 2016-11-03 10:41:49
using channel ORA_DISK_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 11/03/2016 10:41:49
RMAN-06183: datafile or datafile copy /vcboradata/oradata/datafile/system01.dbf (file number 1) larger than MAXSETSIZE
Recovery Manager complete.

RMAN parameters:

RMAN> show all;
using target database control file instead of recovery catalog
RMAN configuration parameters for database with db_unique_name VCBCBS are:
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 31 DAYS;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET PARALLELISM 1;
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 15 G;
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/cbsrmanbackup/rman/snapcf_vcbcbs.f';

Confirm current size of the system01.dbf, as below, used size is 15336.1 which is greater then 15G.

RMANTBS /vcboradata/oradata/datafile/rmantbs.dbf 1000 70.9 929.06
SYSAUX /vcboradata/oradata/datafile/sysaux01.dbf 1400 880.3 519.75
SYSTEM /vcboradata/oradata/datafile/system01.dbf 15400 15336.1 63.94
UNDOTBS1 /vcboradata/oradata/datafile/undotbs01.dbf 4725 97.3 4627.75
USERS /vcboradata/oradata/datafile/users01.dbf 50 15.9 34.13

Workaround:
Increase the size of MAXPIECESIZE RMAN parameter from 15G to 33G. (You can increase it as per your convenience)
More on MAXPIECESIZE:
This parameter is use to set limits on the size of backup pieces. You can also use the MAXSETSIZE parameter on the BACKUP and CONFIGURE commands to set a limit for the size of backup sets.

RMAN> CONFIGURE MAXSETSIZE TO 33G;
old RMAN configuration parameters:
CONFIGURE MAXSETSIZE TO 15 G;
new RMAN configuration parameters:
CONFIGURE MAXSETSIZE TO 33 G;
new RMAN configuration parameters are successfully stored

After above changes, backup successfully completed.

Have a nice time ahead.

Stay Tune. 🙂