Create a Metric Extension (ME) to Monitor FRA Usage on OEM 12C

As we know “Archive Area % Used” metric does not work for using FRA as archive destination when the destination is set to USE_DB_RECOVERY_FILE_DEST. We only receive after “Recovery Area % Used” metric triggers when it hits a Warning threshold of 85% full, and Critical of 97% full.

But the fixed thresholds of 85( Warning )/97( Critical) is not good enough for handling FRA full. So here we develop a customized more flexible way to  monitor and alert when FRA is used as archive destination.

1) Make sure to use FRA for your archive destination

SQL> show parameter recovery

------------------------------------ ----------- ------------------------------
db_recovery_file_dest string +FRA
db_recovery_file_dest_size big integer 100G
log_archive_dest_1  string  location=USE_DB_RECOVERY_FILE_DEST

2) Prepare the Sql script to monitor the Flash Recovery Area destination. In our situation, space_reclaimable is regarded as available space.

select name, 
round(space_limit / 1024/1024/1024) space_limit_in_gb, 
round(space_used / 1024/1024/1024) space_used_in_gb, 
round(space_reclaimable / 1024/1024/1024)space_reclaimable_in_gb,
round( (space_used - space_reclaimable)/ space_limit , 2 )*100 percent_usage
from v$recovery_file_dest;

3) Create a Metric Extension ( ME )

a: Go to Enterprise / Monitoring / Metric Extensions, and then click on Create


b:  For General Properties, Give the rerequired values,  the click NEXT

Target Type: Cluster Database
Name ME$: ME$RACRecoveryAreaSpace
Display Name: RAC Recovery Area Space
Adapter: SQL

c) Enter the query of monitoring FRA usage, the click NEXT


d) For Create New:Columns:

Click Add->New Metric Column, add below columns with supplied properties.



For FRA_NAME column:

For FRA_LIMIT Column:

For FRA_USED Column:


For FRA_PERCENT_USED column, we need set a default threshold by selecting a Comparison Operator and setting Warning and Critical thresholds.

Check all the colums, and click NEXT

e) For Credentials, then click NEXT

f) for TEST, choose a cluster database, then click “Run Test”


g)For Review page, Check all and click Finish if everything is OK.


h) the ME is “Editable” now.

i) Select Actions->Save as Deployable Draft , then the ME changes in to “Deployable Draft” status.

j) Finally, we need apply this ME onto targets( cluster databases).
Select Actions ->Deploy to Targets-> Add, and select the target you wish to deploy to, then click Submit.

k) Check whether the ME is working as expected, go to target home page->Cluster Database->Monitoring->All Metrics:


l) go to target home page->Cluster Database->Monitoring->Metric and Collection Settings:

So, the Metric Extension ( ME) is created successfully, in another post, we will create a Incident Rule which will create an incident and notification for all the over threshold Warning and Critical alerts.

Further more, we will create a Corrective Action against this Metric Extension ( ME ) to to a archive log backup automatically.

This entry was posted in OEM, OEM12c and tagged , , , , , , , . Bookmark the permalink.

2 Responses to Create a Metric Extension (ME) to Monitor FRA Usage on OEM 12C

  1. Pingback: Create an Incident Rule for Metric Extension ( ME ) to Monitor FRA Used in OEM 12C | James Huang Oracle DBA Blog

  2. Pingback: Use Corrective Action ( CA ) to Automate Archivelog Backup When FRA Usage is Over Threshold of Metric Extension ( ME ) in OEM 12C | James Huang Oracle DBA Blog

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