今天一兄弟的库报ORA-09925: Unable to create audit trail file，当时查 df -h有可用空间，文件夹的权限也正确，未df -i查看Inodes使用情况，审计文件夹下有将近24W个文件，初步推測是由于审计生成文件过多导致文件夹所在分区的Inodes用光了，当时删除部分审计TRACE文件后正常未查看 Inodes使用情况。

汇总了下：ORA-09925的原因大致有下面三种：--事实上能够依据报错推断是权限问题还是磁盘空间问题

原因一：文件夹权限问题--文件夹权限被改，无权限向文件夹写审计数据

oracle bin文件夹（实际是整个oracle文件夹）的属主被更改:  --ls -al bin

解决方法

chown -R oracle.oinstall /opt/orace

原因二：确实磁盘没空间了  --df -h

原因三：磁盘Inodes用光--df -i     參考：模拟LINUX磁盘分区有可用空间无可用Inodes时报错：No
space left on device

报错演示样例：--部分网络

演示样例1：能够依据报错信息推断是文件夹权限问题导致不能写入

ORA-09925: Unable to create audit trail file

Linux Error: 13: Permission denied

Additional information: 9925

ORA-09925: Unable to create audit trail file

Linux Error: 13: Permission denied

Additional information: 9925

演示样例2：--仅仅读文件系统--没有写权限（可能是文件系统出问题）

ORA-09925: Unable to create audit trail file  

Linux-x86_64 Error: 30: Read-only file system  

Additional information: 9925  

ORA-01075: you are currently logged on

演示样例3：--没有可用空间

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MOS上的一段描写叙述及解决：

Problem Description -------------------   

Problem occurs when:   $ORACLE_HOME/rdbms/audit directory is full or   $ORACLE_HOME/rdbms/audit directory doesn't exist   as a side effect of this problem oracle asks for password  after connect internal

   

Solution Description  --------------------   

Make space available in $ORACLE_HOME/rdbms/audit by removing files that are  not needed     or    Make sure the directory exists and is readable by oracle    or    Change init.ora audit_file_dest to an existing directory.   Change init.ora parameter means restart
instance as workaround kill pmon.                                                 



Explanation  -----------   

The behavior on Unix is to write a file named ora_<process_id>.aud into   the directory specified by audit_file_dest.    The default directory is /rdbms/audit.    The file will contain an entry for the audited action, which would be internal  logins or startup.
On ports which support an OS audit trail, these records will be   written there.   This feature is not affected by the settings of the audit_trail parameter.

ORA-09925: "Unable to create audit trail file"

Cause: ORACLE was not able to create the file being used to hold   audit trail records.

Action: Check the UNIX error number for a possible operating system error.              

If there is no error, contact ORACLE customer support.

References  ----------

[NOTE:1018924.102] ORA-09925 ON DATABASE STARTUP  [NOTE:1056988.6]   ORA-09925 DURING HOT BACKUPS  [NOTE:21073.1]

OERR:  ORA-9925   "Unable to create audit trail  [BUG:723955]       SQLPLUS ALLOWS DB STARTUP (BUT NOT SHUTDOWN)

IF AUDIT_FILE_DEST DOESN'T EXIST

Search Words  ------------   ORA-09925 audit trail audit_file_dest