Oracle实例经常自动关闭

错误日志

log.xml日志显示

<msg time='2020-03-23T22:54:40.080+08:00' org_id='oracle' comp_id='rdbms'
    type='UNKNOWN' level='16' host_id='5313a10a1aaf'
    host_addr='172.18.0.2' pid='22622'>
    <txt>Errors in file /home/oracle/app/oracle/diag/rdbms/helowin/helowin/trace/helowin_ora_22622.trc:
    ORA-27167: Attempt to determine if Oracle binary image is stored on remote server failed
    ORA-27300: OS system dependent operation:parse_df failed with status: 2
    ORA-27301: OS failure message: No such file or directory
    ORA-27302: failure occurred at: parse failed
    ORA-27303: additional information: Filesystem     1K-blocks     Used Available Use% Mounted on
    overlay         41152812 15343004  23906152  40% /
    </txt>
</msg>

alert_$sid.log日志显示

Fatal NI connect error 12170.

    VERSION INFORMATION:
        TNS for Linux: Version 11.2.0.1.0 - Production
        Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
        TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
    Time: 23-MAR-2020 14:12:48
    Tracing not turned on.
    Tns error struct:
    ns main err code: 12535

TNS-12535: TNS:operation timed out
    ns secondary err code: 12560
    nt main err code: 505

TNS-00505: Operation timed out
    nt secondary err code: 110
    nt OS err code: 0
    Client address: (ADDRESS=(PROTOCOL=tcp)(HOST=120.8.41.88)(PORT=59361))
Mon Mar 23 18:01:51 2020
PMON (ospid: 20541): terminating the instance due to error 474
Instance terminated by PMON, pid = 20541
Starting ORACLE instance (normal)
Errors in file /home/oracle/app/oracle/diag/rdbms/helowin/helowin/trace/helowin_ora_22622.trc:
ORA-27167: Attempt to determine if Oracle binary image is stored on remote server failed
ORA-27300: OS system dependent operation:parse_df failed with status: 2
ORA-27301: OS failure message: No such file or directory
ORA-27302: failure occurred at: parse failed
ORA-27303: additional information: Filesystem     1K-blocks     Used Available Use% Mounted on
overlay         41152812 15343004  23906152  40% /
Image consistency checking encountered an error, checking disabled

问题原因

12170错误

为了节省连接资源，Oracle会在连接连接长时间未使用时自动断开，并写入日志alert中。

解决办法

设置自动断开连接的时间(即设置DCD)
关闭ADR