Archived redo log retention
If a primary DB instance has no cross-Region read replicas, Amazon RDS for Oracle keeps a minimum of two hours of archived redo logs on the source DB instance. This is true regardless of the setting for
archivelog retention hoursinrdsadmin.rdsadmin_util.set_configuration.
So we have to observe storage free space if we use Data Guard (Read Replica) with RDS.
Normal Single DB
SELECT GROUP#, THREAD#, SEQUENCE#, ARCHIVED, STATUS FROM V$STANDBY_LOG;
no rows selected
set linesize 200
col MEMBER for a60
SELECT GROUP#, MEMBER, TYPE, STATUS FROM V$LOGFILE WHERE TYPE = 'STANDBY';
no rows selectedAfter Created Replica
SQL> SELECT GROUP#, THREAD#, SEQUENCE#, ARCHIVED, STATUS FROM V$STANDBY_LOG;
GROUP# THREAD# SEQUENCE# ARC STATUS
---------- ---------- ---------- --- ----------
5 1 0 YES UNASSIGNED
6 1 0 YES UNASSIGNED
7 1 0 YES UNASSIGNED
8 1 0 YES UNASSIGNED
9 1 0 YES UNASSIGNED
SQL> SELECT GROUP#, MEMBER, TYPE, STATUS FROM V$LOGFILE WHERE TYPE = 'STANDBY';
GROUP# MEMBER TYPE STATUS
---------- ------------------------------------------------------------ ------- -------
5 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_5_n508qdnf_.log STANDBY
6 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_6_n508qdwc_.log STANDBY
7 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_7_n508qf43_.log STANDBY
8 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_8_n508qfc4_.log STANDBY
9 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_9_n508qfl5_.log STANDBY
SQL> SELECT GROUP#, MEMBER, STATUS, TYPE FROM V$LOGFILE;
GROUP# MEMBER STATUS TYPE
---------- ------------------------------------------------------------ ------- -------
1 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_1_n0f7xd93_.log ONLINE
2 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_2_n0f7xcp7_.log ONLINE
3 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_3_n0f7xc5f_.log ONLINE
4 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_4_n0f7xf7n_.log ONLINE
5 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_5_n508qdnf_.log STANDBY
6 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_6_n508qdwc_.log STANDBY
7 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_7_n508qf43_.log STANDBY
8 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_8_n508qfc4_.log STANDBY
9 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_9_n508qfl5_.log STANDBYAfter Promoting a read replica
SQL> SELECT GROUP#, THREAD#, SEQUENCE#, ARCHIVED, STATUS FROM V$STANDBY_LOG;
no rows selected
SQL> SELECT GROUP#, MEMBER, STATUS, TYPE FROM V$LOGFILE;
GROUP# MEMBER STATUS TYPE
---------- -------------------------------------------------------------------------------- ------- -------
1 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_1_n0f7xd93_.log ONLINE
2 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_2_n0f7xcp7_.log ONLINE
3 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_3_n0f7xc5f_.log ONLINE
4 /rdsdbdata/db/ORCL_A/onlinelog/o1_mf_4_n0f7xf7n_.log ONLINE
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