Redo log group 변경 (디렉토리, 사이즈)

리두 로그 그룹 추가/삭제를 통해 디렉토리 및 사이즈를 변경해본다.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/redo01.log                     50 NO  CURRENT
         2 /home/oracle/oradata/testdb/redo02.log                     50 NO  INACTIVE
         3 /home/oracle/oradata/testdb/redo03.log                     50 NO  INACTIVE

#새로운 리두 로그 그룹 4, 5를 추가한다.
#리두 로그 그룹 1, 2, 3을 삭제하기 위해 리두 로그 그룹은 최소 2개가 존재해야 한다.
SQL> alter database add logfile group 4
  2  '/home/oracle/oradata/testdb/redo04.log' size 5m;

Database altered.

SQL> alter database add logfile group 5
  2  '/home/oracle/oradata/testdb/redo05.log' size 5m;

Database altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/redo01.log                     50 NO  CURRENT
         2 /home/oracle/oradata/testdb/redo02.log                     50 NO  INACTIVE
         3 /home/oracle/oradata/testdb/redo03.log                     50 NO  INACTIVE
         4 /home/oracle/oradata/testdb/redo04.log                      5 YES UNUSED
         5 /home/oracle/oradata/testdb/redo05.log                      5 YES UNUSED

#리두 로그 그룹 4, 5를 추가한 후 CURRENT를 새로 추가한 리두 로그 그룹으로 변경한다.
SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

#리두 로그 그룹 1, 2, 3을 삭제하기 위해 수동으로 checkpoint를 발생시킨다.
SQL> alter system checkpoint;

System altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/redo01.log                     50 NO  INACTIVE
         2 /home/oracle/oradata/testdb/redo02.log                     50 NO  INACTIVE
         3 /home/oracle/oradata/testdb/redo03.log                     50 NO  INACTIVE
         4 /home/oracle/oradata/testdb/redo04.log                      5 NO  INACTIVE
         5 /home/oracle/oradata/testdb/redo05.log                      5 NO  CURRENT

#리두 로그 그룹 5를 CURRENT 상태로 만든 후 리두 로그 그룹 1, 2, 3을 삭제한다.
SQL> alter database drop logfile group 1;

Database altered.

SQL> alter database drop logfile group 2;

Database altered.

SQL> alter database drop logfile group 3;

Database altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         4 /home/oracle/oradata/testdb/redo04.log                      5 NO  INACTIVE
         5 /home/oracle/oradata/testdb/redo05.log                      5 NO  CURRENT

#새로운 리두 로그 그룹 1, 2, 3을 추가하기 위한 새로운 디렉토리를 생성한다.
#디렉토리를 생성하지 않고 추가할 경우 디렉토리 문제로 에러가 발생한다.
SQL> !mkdir -p /home/oracle/oradata/testdb/log

#새로운 디렉토리에 리두 로그 그룹 1, 2, 3을 추가한다.
SQL> alter database add logfile group 1
  2  '/home/oracle/oradata/testdb/log/redo01.log' size 5m;

Database altered.

SQL> alter database add logfile group 2
  2  '/home/oracle/oradata/testdb/log/redo02.log' size 5m;

Database altered.

SQL> alter database add logfile group 3
  2  '/home/oracle/oradata/testdb/log/redo03.log' size 5m;

Database altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/log/redo01.log                  5 YES UNUSED
         2 /home/oracle/oradata/testdb/log/redo02.log                  5 YES UNUSED
         3 /home/oracle/oradata/testdb/log/redo03.log                  5 YES UNUSED
         4 /home/oracle/oradata/testdb/redo04.log                      5 NO  INACTIVE
         5 /home/oracle/oradata/testdb/redo05.log                      5 NO  CURRENT

#기존 리두 로그 그룹 4, 5를 삭제하기 위해 강제로 로그 스위치를 발생시킨다.
SQL> alter system switch logfile;

System altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/log/redo01.log                  5 NO  ACTIVE
         2 /home/oracle/oradata/testdb/log/redo02.log                  5 NO  ACTIVE
         3 /home/oracle/oradata/testdb/log/redo03.log                  5 NO  ACTIVE
         4 /home/oracle/oradata/testdb/redo04.log                      5 NO  CURRENT
         5 /home/oracle/oradata/testdb/redo05.log                      5 NO  ACTIVE

SQL> alter system switch logfile;

System altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/log/redo01.log                  5 NO  ACTIVE
         2 /home/oracle/oradata/testdb/log/redo02.log                  5 NO  ACTIVE
         3 /home/oracle/oradata/testdb/log/redo03.log                  5 NO  ACTIVE
         4 /home/oracle/oradata/testdb/redo04.log                      5 NO  ACTIVE
         5 /home/oracle/oradata/testdb/redo05.log                      5 NO  CURRENT

#강제 로그 스위치 발생 경과로 보아 UNUSED에서 바로 CURRENT가 되지 않는다.
#CURRENT의 순서는 4 -> 5 -> 4 -> 1 순이며 세번째 4가 CURRENT일때 1, 2, 3의 상태는 ACTIVE가 된다.
SQL> alter system switch logfile;

System altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/log/redo01.log                  5 NO  CURRENT
         2 /home/oracle/oradata/testdb/log/redo02.log                  5 NO  ACTIVE
         3 /home/oracle/oradata/testdb/log/redo03.log                  5 NO  ACTIVE
         4 /home/oracle/oradata/testdb/redo04.log                      5 NO  ACTIVE
         5 /home/oracle/oradata/testdb/redo05.log                      5 NO  ACTIVE

#기존 리두 로그 그룹 4, 5를 삭제하기 위해 강제로 checkpoint를 발생시킨다.
SQL> alter system checkpoint;

System altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/log/redo01.log                  5 NO  CURRENT
         2 /home/oracle/oradata/testdb/log/redo02.log                  5 NO  INACTIVE
         3 /home/oracle/oradata/testdb/log/redo03.log                  5 NO  INACTIVE
         4 /home/oracle/oradata/testdb/redo04.log                      5 NO  INACTIVE
         5 /home/oracle/oradata/testdb/redo05.log                      5 NO  INACTIVE

#기존 리두 로그 그룹 4, 5를 삭제한다.
SQL> alter database drop logfile group 4;

Database altered.

SQL> alter database drop logfile group 5;

Database altered.

SQL> select a.group#, a.member, b.bytes/1024/1024 MB, b.archived, b.status
  2  from v$logfile a, v$log b
  3  where a.group# = b.group#
  4  order by 1, 2;

    GROUP# MEMBER                                                     MB ARC STATUS
---------- -------------------------------------------------- ---------- --- ----------------
         1 /home/oracle/oradata/testdb/log/redo01.log                  5 NO  CURRENT
         2 /home/oracle/oradata/testdb/log/redo02.log                  5 NO  INACTIVE
         3 /home/oracle/oradata/testdb/log/redo03.log                  5 NO  INACTIVE

#SQL에서 리두 로그 그룹을 DROP 하더라도 실제 OS 파일은 삭제되지 않는다.
#따라서 확인한 후 해당 리두 로그 파일을 삭제한다.
SQL> !ls /home/oracle/oradata/testdb/
control01.ctl  example01.dbf  redo02.log  redo05.log    temp01.dbf
control02.ctl  log            redo03.log  sysaux01.dbf  undotbs01.dbf
control03.ctl  redo01.log     redo04.log  system01.dbf  users01.dbf

SQL> !rm -rf /home/oracle/oradata/testdb/redo*.log

SQL> !ls /home/oracle/oradata/testdb/
control01.ctl  control03.ctl  log           system01.dbf  undotbs01.dbf
control02.ctl  example01.dbf  sysaux01.dbf  temp01.dbf    users01.dbf

SQL>