Asm Diskgroup success Mount And Umount messages in

April 27, 2009 | tags | views 101

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Asm Diskgroup success Mount And Umount messages in database alert.log

文档ID：361173.1         类型：PROBLEM

Applies to:

Oracle Server - Enterprise Edition - Version: 10.2 to 10.2
This problem can occur on any platform.

Symptoms:

Database alert.log shows the following messages frequently:

SUCCESS: diskgroup LOG was mounted
SUCCESS: diskgroup LOG was dismounted
SUCCESS: diskgroup LOG was mounted
SUCCESS: diskgroup LOG was dismounted

Cause:

This is intended behavior.

From bug:4465015 Asm Diskgroup For Flash Recovery Area Display Mount And Dismount In Db Alert Log (Not published)

This is expected behavior. The messages you see are not errors (that is why  they are prefixed with "SUCCESS"). The database instance is creating and then closing archive logs one at a time in the LOG disk group.
Whenever a database closes its last file in a disk group, it dismounts the disk group.
Whenever a database accesses a disk group when it does not have any other files open in the disk group, it mounts the disk group.

If a diskgroup is used only for flashback feature and rman backups in a database, many log messages are seen in alert.log. However, the same may also occur for diskgroups keeping datafiles but in less frequency.

Solution:

This is intended behavior. No solution is required. If you do not want to see the log messages frequently, you can put a mirrored control-file, or mirrored online redo, or dummy online tablespace data file on the diskgroup. This message will not be output frequently in this case. Because CKPT keeps opening a control-file, LGWR keeps opening an online redo, DBW keeps opening an online tablespace data file. So, the diskgroup is not dismounted until the database shutdown.