Oracle зеркалирование online redo logs
У нас есть три группы журналов:
SQL> select member from v$logfile;
MEMBER
----------------------------------------------------------------------
/oradata/orcl/redo01.log
/oradata/orcl/redo02.log
/oradata/orcl/redo03.log
Видно что в каждой группе журналов по одному файлу:
SQL> select member from v$logfile where group# = '1';
MEMBER
----------------------------------------------------------------------
/oradata/orcl/redo01.log
SQL> select member from v$logfile where group# = '2';
MEMBER
----------------------------------------------------------------------
/oradata/orcl/redo02.log
SQL> select member from v$logfile where group# = '3';
MEMBER
--------------------------------------------------------------------
/oradata/orcl/redo03.log
Добавляем в каждую группу файл журнала:
SQL> alter database add logfile member '/oradata/orcl/redo01a.log' to group 1;
SQL> alter database add logfile member '/oradata/orcl/redo02a.log' to group 2;
alter database add logfile member '/oradata/orcl/redo03a.log' to group 3;
Проверяем количество журналов в группе:
SQL> select member from v$logfile where group# = '1';
MEMBER
----------------------------------------------------------------------
/oradata/orcl/redo01.log
/oradata/orcl/redo01a.log