早上检查一ORACLE数据库的RMAN备份的邮件时，发现出现了ORA-27072: File I/O error等错误，具体信息如下所示：
channel ORA_DISK_1: starting piece 1 at 23-MAR-15
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup plus archivelog command at 03/23/2015 03:48:02
ORA-19502: write error on file "/u04/backup/backupsets/ora_df875072537_s15615_s1", blockno 182657 (blocksize=8192)ORA-27072: File I/O error
Linux-x86_64 Error: 9: Bad file descriptor
Additional information: 4
Additional information: 182657
Additional information: 700416
Recovery Manager complete.
关于ORA-03002与ORA-27072错误的描述，如下所示
[oracle@DB-Server-03 ~]$ oerr ora 19502
19502, 00000, "write error on file "%s", blockno %s (blocksize=%s)"
// *Cause: write error on output file
// *Action: check the file
[oracle@DB-Server-03 ~]$ oerr ora 27072
27072, 00000, "File I/O error"
// *Cause: read/write/readv/writev system call returned error, additional
// information indicates starting block number of I/O
// *Action: check errno
RMAN备份出现这个错误是在生成备份集时，文件I/O发生错误，因为/u04分区空间不足导致RMAN备份无法写入数据，我们也收到了磁盘分区告警的邮件。如下所示。
