ORA-19809 归档空间未定期清理，导致闪回空间不足

alert输出提示

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You have following choices to free up space from recovery area:
1. Consider changing RMAN RETENTION POLICY. If you are using Data Guard,
   then consider changing RMAN ARCHIVELOG DELETION POLICY.
2. Back up files to tertiary device such as tape using RMAN
   BACKUP RECOVERY AREA command.
3. Add disk space and increase db_recovery_file_dest_size parameter to
   reflect the new space.
4. Delete unnecessary files using RMAN DELETE command. If an operating
   system command was used to delete files, then use RMAN CROSSCHECK and
   DELETE EXPIRED commands.
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Errors in file /u01/app/oracle/diag/rdbms/skyhost/skyHost/trace/skyHost_ora_3116.trc:
ORA-19809: limit exceeded for recovery files
ORA-19804: cannot reclaim 45920768 bytes disk space from 4070572032 limit
ARCH: Error 19809 Creating archive log file to '/u01/app/oracle/flash_recovery_area/SKYHOST/archivelog/2017_11_10/o1_mf_1_113_%u_.arc'
Errors in file /u01/app/oracle/diag/rdbms/skyhost/skyHost/trace/skyHost_ora_3116.trc:
ORA-16038: log 2 sequence# 113 cannot be archived
ORA-19809: limit exceeded for recovery files
ORA-00312: online log 2 thread 1: '/u01/app/oracle/oradata/skyHost/redo02.log'

解决办法

1. 数据库启动到mount状态
2. 系统上删除归档文件（先做备份）
3. RMAN上删除这些归档记录crosscheck archivelog all;delete expired archivelog all;
4. 数据库打开 alter database open;
5. 之后维护中 调整db_recovery_file_dest_size的大小；或者定时清理日志文件，监控文件夹容量