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记一次RAC归档满及DB_RECOVERY_FILE_DEST_SIZE理解
一、RAC归档满及处理
[root@rac1 ~]# crsctl stat res -t
--------------------------------------------------------------------------------
NAME TARGET STATE SERVER STATE_DETAILS
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.CRS.dg
ONLINE ONLINE rac1
ONLINE ONLINE rac2
ora.DATA.dg
ONLINE ONLINE rac1
ONLINE ONLINE rac2
ora.LISTENER.lsnr
ONLINE ONLINE rac1
ONLINE ONLINE rac2
ora.asm
ONLINE ONLINE rac1 Started
ONLINE ONLINE rac2 Started
ora.gsd
OFFLINE OFFLINE rac1
OFFLINE OFFLINE rac2
ora.net1.network
ONLINE ONLINE rac1
ONLINE ONLINE rac2
ora.ons
ONLINE ONLINE rac1
ONLINE ONLINE rac2
ora.registry.acfs
ONLINE ONLINE rac1
ONLINE ONLINE rac2
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.LISTENER_SCAN1.lsnr
1 ONLINE ONLINE rac2
ora.cvu
1 ONLINE ONLINE rac2
ora.doudou.db
1 ONLINE INTERMEDIATE rac1 Stuck Archiver
2 ONLINE INTERMEDIATE rac2 Stuck Archiver
ora.oc4j
1 ONLINE ONLINE rac2
ora.rac1.vip
1 ONLINE ONLINE rac1
ora.rac2.vip
1 ONLINE ONLINE rac2
ora.scan1.vip
1 ONLINE ONLINE rac2
--初步推断,归档满了
查看alert.log
ARC2: Error 19809 Creating archive log file to '+DATA'
Errors in file /Oracle/app/oracle/diag/rdbms/doudou/doudou1/trace/doudou1_arc3_7838.trc:
ORA-19815: WARNING: db_recovery_file_dest_size of 8388608000 bytes is 100.00% used, and has 0 remaining bytes available.
************************************************************************
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.
--从alert.log来看,确实归档满了,而且还给出了解决办法。
解决办法:(测试库,所以我就暴力处理了)
[oracle@rac1 ~]$ rman target /
RMAN> delete archivelog all;
二、DB_RECOVERY_FILE_DEST_SIZE理解
SYS@doudou1> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 279
Next log sequence to archive 279
Current log sequence 280
SYS@doudou2> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 188
Next log sequence to archive 188
Current log sequence 189
SYS@doudou1> show parameter DB_RECOVERY_FILE_DEST
NAME TYPE VALUE
------------------------------------ ---------------------- ------------------------------
db_recovery_file_dest string +DATA
db_recovery_file_dest_size big integer 8000M
ASMCMD> du +data/doudou/archivelog
Used_MB Mirror_used_MB
6816 6816
--为什么我们的归档目录没有使用到8000M,但是不能使用了呢?是不是有什么错误呢,其实这是正确的,只是自己理解错误而已。
下面是官档对DB_RECOVERY_FILE_DEST_SIZE的解释
The DB_RECOVERY_FILE_DEST_SIZE setting does not include the following kinds of disk overhead:
Block 0 or the operating system block header of each Oracle Database file is not included.
Allow an extra 10% for this data when computing the actual disk usage required for the fast recovery area.
DB_RECOVERY_FILE_DEST_SIZE does not indicate the real size occupied on disk when the underlying file system is mirrored, compressed, or affected by overhead not known to Oracle Database.
For example, if the recovery area is on a two-way mirrored ASM disk group, each file of x bytes occupies 2x bytes on the ASM disk group. In this case, set DB_RECOVERY_FILE_DEST_SIZE to no more than half the size of the disks for the ASM disk group. Likewise, when using a three-way mirrored ASM disk group, DB_RECOVERY_FILE_DEST_SIZE must be no greater than one third the size of the disks in the disk group, and so on.
总结:
1.DB_RECOVERY_FILE_DEST_SIZE这个参数不是OS限制参数,所以不要以OS目录的思想来限制DB_RECOVERY_FILE_DEST_SIZE的大小,另一点就是DB_RECOVERY_FILE_DEST_SIZE参数会留有10%用于fast recovery area。
2.RAC归档量的使用是跟节点数有关的,例如有2个节点的RAC,那归档量将是2个节点的和,也就是每个节点只能使用DB_RECOVERY_FILE_DEST_SIZE的一半,如果是多个节点则是N/A(N DB_RECOVERY_FILE_DEST_SIZE可用值,A节点数)。
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