手动清理Oracle审计记录

分手后的思念是犯贱 2022-08-09 11:45 227阅读 0赞

Oracle 数据库审计功能非常强大，通常包括标准审计(包括用户级审计和系统级审计)和细粒度审计。尽管如此，一不小心就容易造成性能问题。同时会把系统表空间给撑爆。下面的内容描述的是如何将审计从系统表空间剥离以及清理Oracle审计记录，供大家参考。

# 一、审计的相关配置 #

--环境
    SQL> select * from v$version where rownum=1;
    
    BANNER
    --------------------------------------------------------------------------------
    Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
    
    SQL> show parameter audit
    
    NAME                                 TYPE        VALUE
    ------------------------------------ ----------- ------------------------------
    audit_file_dest                      string      /home/oraprod/app/product/11.2
                                                     .0/dbhome_1/rdbms/audit
    audit_sys_operations                 boolean     FALSE
    audit_syslog_level                   string
    audit_trail                          string      DB  --此值为当前Oracle 11gR2缺省配置
    
    --从下面的查询中可以看出，当前的审计位于system表空间
    SQL> col segment_name FOR a10
    SQL> SELECT owner,segment_name,tablespace_name FROM dba_segments WHERE segment_name ='AUD$';
    
    OWNER                          SEGMENT_NA TABLESPACE_NAME
    ------------------------------ ---------- ------------------------------
    SYS                            AUD$       SYSTEM

# 二、修改审计存储表空间 #

新增一个表空间用于存储审计日志
    SQL> CREATE tablespace audit_data datafile '/home/oracle/app/oradata/orcl/audit01.dbf'
      2  SIZE 100M autoextend ON NEXT 50M;
    
    SQL> @tbs_free.sql
    
    TABLESPACE_NAME                USED (MB FREE (MB TOTAL (M PER_FR
    ------------------------------ -------- -------- -------- ------
    AUDIT_DATA                            1    1,199    1,200  100 %
    SYSAUX                            1,133       77    1,210    6 %
    SYSTEM                            1,875       15    1,890    1 %
    
    -- 设定审计数据存放表空间 
    SQL> BEGIN
      2    DBMS_AUDIT_MGMT.SET_AUDIT_TRAIL_LOCATION(
      3      AUDIT_TRAIL_TYPE => DBMS_AUDIT_MGMT.AUDIT_TRAIL_AUD_STD,
      4      AUDIT_TRAIL_LOCATION_VALUE => 'AUDIT_DATA'
      5    );
      6  END;
      7  /
    BEGIN
    *
    ERROR at line 1:
    ORA-46267: Insufficient space in 'AUDIT_DATA' tablespace, cannot complete
    operation
    ORA-06512: at "SYS.DBMS_AUDIT_MGMT", line 1576
    ORA-06512: at line 2
    -- 错误提示，尽管我们使用了自动扩展表空间，依旧提示空间不够
    
    -- 查看当前审计数据大小，如下为1152MB
    SQL> select segment_name,bytes/1024/1024 from dba_segments where segment_name='AUD$';
    
    SEGMENT_NAME              BYTES/1024/1024
    ------------------------- ---------------
    AUD$                                 1152
    
    -- 下面调整数据文件大小
    SQL> alter database datafile '/home/oracle/app/oradata/orcl/audit01.dbf' resize 1200m;
    
    Database altered.
    
    -- 再次设定审计数据存放表空间OK 
    SQL> BEGIN
      2    DBMS_AUDIT_MGMT.SET_AUDIT_TRAIL_LOCATION(
      3      AUDIT_TRAIL_TYPE => DBMS_AUDIT_MGMT.AUDIT_TRAIL_AUD_STD,
      4      AUDIT_TRAIL_LOCATION_VALUE => 'AUDIT_DATA'
      5    );
      6  END;
      7  /
    
    PL/SQL procedure successfully completed.
    
    Elapsed: 00:02:23.10
    --整个过程花费了2m23s，主要是期间进行了数据搬迁
    
    SQL> SELECT owner,segment_name,tablespace_name FROM dba_segments WHERE segment_name ='AUD$';
    
    OWNER                          SEGMENT_NAME                   TABLESPACE_NAME
    ------------------------------ ------------------------------ ------------------------------
    SYS                            AUD$                           AUDIT_DATA
    
    SQL> @tbs_free.sql
    
    TABLESPACE_NAME                USED (MB FREE (MB TOTAL (M PER_FR
    ------------------------------ -------- -------- -------- ------
    AUDIT_DATA                        1,153       47    1,200    4 %
    SYSAUX                            1,143       67    1,210    6 %
    SYSTEM                              724    1,166    1,890   62 %
    
    -- 从上面的这个查询可以看出，原来位于system表空间的AUD$被迁移到了AUDIT_DATA
    -- 相应地AUDIT_DATA表空间已使用增加，而SYSTEM表空间使用率下降
    
    -- 查看审计数据字典配置信息
    SQL> col PARAMETER_NAME FOR a30
    SQL> col PARAMETER_VALUE FOR a15
    SQL> col AUDIT_TRAIL FOR a20
    SQL> SELECT PARAMETER_NAME, PARAMETER_VALUE, AUDIT_TRAIL
      2  FROM DBA_AUDIT_MGMT_CONFIG_PARAMS
      3  WHERE audit_trail = 'STANDARD AUDIT TRAIL';
    
    PARAMETER_NAME                 PARAMETER_VALUE AUDIT_TRAIL
    ------------------------------ --------------- --------------------
    DB AUDIT TABLESPACE            AUDIT_DATA      STANDARD AUDIT TRAIL
    DB AUDIT CLEAN BATCH SIZE      10000           STANDARD AUDIT TRAIL

# 三、清除审计记录 #

通过这个过程设定清除间隔
    SQL> BEGIN
      2    DBMS_AUDIT_MGMT.init_cleanup(
      3      audit_trail_type         => DBMS_AUDIT_MGMT.AUDIT_TRAIL_ALL,
      4      default_cleanup_interval => 120 /* hours */);
      5  END;
      6  /
    
    PL/SQL procedure successfully completed.
    
    -- 下面严验证审计日志清除是否已开启
    SQL> SET SERVEROUTPUT ON
    SQL> BEGIN
      2    IF DBMS_AUDIT_MGMT.is_cleanup_initialized(DBMS_AUDIT_MGMT.AUDIT_TRAIL_AUD_STD) THEN
      3      DBMS_OUTPUT.put_line('YES');
      4    ELSE
      5      DBMS_OUTPUT.put_line('NO');
      6    END IF;
      7  END;
      8  /
    YES
    
    PL/SQL procedure successfully completed.
    
    SQL> select segment_name,bytes/1024/1024 from dba_segments where segment_name='AUD$';
    
    SEGMENT_NAME        BYTES/1024/1024
    ------------------- ---------------
    AUD$                           1152
    
    SQL> select 'Leshami' As author,'http://blog.csdn.net/leshami' as Blog from dual;
    
    AUTHOR  BLOG
    ------- ----------------------------
    Leshami http://blog.csdn.net/leshami
    
    SQL> select count(*) from AUD$;
    
      COUNT(*)
    ----------
       5908086
    
    SQL> select min(ntimestamp#) from aud$;
    
    MIN(NTIMESTAMP#)
    ---------------------------------------------------------------------------
    20-AUG-14 06.11.09.901253 AM
    
    -- 设定归档间隔
    SQL> BEGIN
      2  DBMS_AUDIT_MGMT.set_last_archive_timestamp(
      3  audit_trail_type  => DBMS_AUDIT_MGMT.AUDIT_TRAIL_AUD_STD,
      4  last_archive_time => SYSTIMESTAMP-10);
      5  END;
      6  /
    
    PL/SQL procedure successfully completed
    
    --查看设定的归档间隔
    SQL> SELECT * FROM dba_audit_mgmt_last_arch_ts;
    
    AUDIT_TRAIL          RAC_INSTANCE LAST_ARCHIVE_TS
    -------------------- ------------ ---------------------------------------------------------------------------
    STANDARD AUDIT TRAIL            0 09-OCT-15 01.27.17.000000 PM +00:00
    
    --通过调用DBMS_AUDIT_MGMT.clean_audit_trail进行手动清理审计日志
    BEGIN
      DBMS_AUDIT_MGMT.clean_audit_trail(
       audit_trail_type        => DBMS_AUDIT_MGMT.AUDIT_TRAIL_AUD_STD,
       use_last_arch_timestamp => TRUE);
    END;
    /
    
    DBMS_AUDIT_MGMT.clean_audit_trail
    This procedure deletes audit trail records. The CLEAN_AUDIT_TRAIL procedure is usually called after the 
    SET_LAST_ARCHIVE_TIMESTAMP Procedure has been used to set the last archived timestamp for the audit records.
    
    --也可以通过创建一个purge Job来进行清理已归档的历史审计记录
    SQL> BEGIN
      2    DBMS_AUDIT_MGMT.CREATE_PURGE_JOB(
      3      AUDIT_TRAIL_TYPE           => DBMS_AUDIT_MGMT.AUDIT_TRAIL_AUD_STD,
      4      AUDIT_TRAIL_PURGE_INTERVAL => 24 /* hours */,
      5      AUDIT_TRAIL_PURGE_NAME     => 'Daily_Audit_Purge_Job',
      6      USE_LAST_ARCH_TIMESTAMP    => TRUE
      7    );
      8  END;
      9  /
    
    PL/SQL procedure successfully completed.
    
    -- 本次测试使用了job进行清理，注，上面的purge job 并非使用DBMS_SCHEDULER.CREATE_JOB创建
    -- 执行job用于清理归档，通过观察，由于redo log size为50MB，切换较为频繁，花费了19分钟
    -- 同时伴随有Checkpoint not complete等待事件，可见redo size过小
    SQL> exec DBMS_SCHEDULER.RUN_JOB(job_name => 'SYS.DAILY_AUDIT_PURGE_JOB');
    
    PL/SQL procedure successfully completed.
    
    Elapsed: 00:19:26.38
    
    SQL> select count(*) from AUD$;
    
      COUNT(*)
    ----------
            12
    
    --经查看，清理后空间并没有释放 
    SQL> select segment_name,bytes/1024/1024 from dba_segments where segment_name='AUD$';
    
    SEGMENT_NAME                   BYTES/1024/1024
    ------------------------------ ---------------
    AUD$                                      1152
    
    SQL> alter table sys.aud$ shrink space cascade;
    alter table sys.aud$ shrink space cascade
    *
    ERROR at line 1:
    ORA-10636: ROW MOVEMENT is not enabled
    
    SQL> alter table sys.aud$ enable row movement;
    
    Table altered.
    
    SQL> alter table sys.aud$ shrink space cascade;
    
    Table altered.
    
    SQL> alter table sys.aud$ disable row movement;
    
    Table altered.
    
    -- 下面的查询可以看到，空间已经被释放
    SQL> select segment_name,bytes/1024/1024 from dba_segments where segment_name='AUD$';
    
    SEGMENT_NAME         BYTES/1024/1024
    -------------------- ---------------
    AUD$                           .0625

## 四、小结 ##

a、对于Oracle 11g，审计功能默认被开启，因此如果在必须启用的情况下应考虑性能影响；  
b、开启审计的情况下，建议将审计从system或sysaux表空间剥离，使用单独的表空间；  
c、对于历史审计日志的清除，应考虑清除期间所带来的性能影响；  
d、调用DBMS\_AUDIT\_MGMT.SET\_AUDIT\_TRAIL\_LOCATION这个过程已经开始了搬迁过程，如果审计日志很庞大，应考虑IO影响；  
e、审计日志的清除需要先设定归档，已归档的审计日志会被清理;  
f、也可以通过trunate table aud$ reuse storage以及deallocate非常规方式来处理。