RMAN > backup as backupset datafile 1 ;

Starting backup at 25-JUL-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=146 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=/u02/app/oracle/oradata/kkmdb/system01.dbf
channel ORA_DISK_1: starting piece 1 at 25-JUL-12
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 07/25/2012 11:20:52
ORA-19502: write error on file "/u02/app/oracle/fra/KKMDB/backupset/2012_07_25/o1_mf_nnndf_TAG20120725T112032_%u_.bkp", blockno 64129 (blocksize=8192)
ORA-27072: File I/O error
Linux-x86_64 Error: 2: No such file or directory
Additional information: 4
Additional information: 64129
Additional information: 532480
 

자꾸 이런 error가 뜹니다.

어떻게 해결 할수 있을까요