饿，没法修改了。补充下环境：

主机：
rhel 7.6，备机 centos 7.9

提示已经很明显了 删了56.dbf 再试试看 ORA-19504: failed to create file “/nfs/56.dbf”
ORA-27038: created file already exists

回复：

没用的，报错是56.dbf文件存在，我重新命令备份为34.dbf（34.dbf事先不存在），报同样的错。

大概就是文件刷刷刷写完，大小也在增长，最后一步就报文件存在了。

直接 mount -t nfs 1.1.1.1:/data /nfs ，写那么多参数估计有影响

@cqiwen

不行哦。。。78.dbf在我操作之前是不存在的

RMAN>  backup datafile 1 format '/nfs/78.dbf';

Starting backup at 10-AUG-21
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=1814 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/erpdb/system01.dbf
channel ORA_DISK_1: starting piece 1 at 10-AUG-21
channel ORA_DISK_1: finished piece 1 at 10-AUG-21
piece handle=/nfs/78.dbf tag=TAG20210810T172811 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 10-AUG-21
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 08/10/2021 17:28:29
ORA-19504: failed to create file "/nfs/78.dbf"
ORA-27038: created file already exists
Additional information: 1

检查下NFS那边的情况
看下
nfs服务器cat /etc/exports 配置参数
客户端 cat /etc/fstab 配置参数

@DonACe

服务器：

[root@nfs data]# cat /etc/exports
/data/	1.1.1.1.0/24(rw,sync,no_root_squash,no_all_squash

客户端我还没有写到fstab里，只是mount挂载了。

另外，和nfs服务器linux本身的权限有关系吗？

/etc/exports参数修改成这样试试rw,sync,no_wdelay,insecure_locks,no_root_squash
也看下挂载目录的权限和属组

@DonACE

还是不行呢。。。

RMAN> backup datafile 1 format '/nfs/1.dbf';

Starting backup at 10-AUG-21
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=1814 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/erpdb/system01.dbf
channel ORA_DISK_1: starting piece 1 at 10-AUG-21
channel ORA_DISK_1: finished piece 1 at 10-AUG-21
piece handle=/nfs/1.dbf tag=TAG20210810T175559 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 10-AUG-21
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 08/10/2021 17:56:16
ORA-19504: failed to create file "/nfs/1.dbf"
ORA-27038: created file already exists
Additional information: 1

在主机上看：

[oracle@oracle ~]$ ll /nfs
total 2727888
-rw-r----- 1 oracle oinstall 859807744 Aug 10 17:56 1.dbf
-rw-r----- 1 oracle oinstall 859807744 Aug 10 12:43 56.dbf
-rw-r----- 1 oracle oinstall 859807744 Aug 10 17:28 78.dbf

其中1是按照刚才的新参数挂载的。56、78.dbf都是之前挂载的。

感觉像是权限不对？是不是应该改成755…

经过群里专家指导，在nfs服务器上新建了oracle用户属于oinstall组

[root@nfs ~]# groupadd oinstall
[root@nfs ~]# groupadd dba
[root@nfs ~]# useradd -g oinstall -G dba oracle
[root@nfs ~]# id oracle
uid=1001(oracle) gid=1001(oinstall) groups=1001(oinstall),1002(dba)

exports参数如下：

/data/ 1.1.1.1/24(rw,all_squash,sync,anonuid=1001,anongid=1001)

挂载参数如下：

mount -v -t nfs -o rw,bg,noac,hard,nointr,rsize=32768,wsize=32768,tcp,actimeo=0,vers=3,timeo=600,nolock 1.1.1.1:/data /nfs

报错依旧。。。。