ORA-38729: Not enough flashback database log data to do FLASHBACK.

Just check the oldest flashback time available>

select oldest_flashback_time from v$flashback_database_log;

Cause:

We need to have the required archive logs in the archive destination at the time of flashback.

Like, there could be a  backup script is archiving all the archivelogs and purging it from the ASM, hence, we cannot flashback with the error that it cannot locate the log files.
 
Resolution:
 
That is, if the flashback database command does not work in SQLPlus because a needed archive log was deleted after an RMAN backup, execute the flashback database command from RMAN. RMAN will flashback the database, restore the missing archive log(s) and apply the logs as needed.

Then 'alter database open resetlogs ;' is executed after the flashback database as normal.

 

Ref: https://support.oracle.com Document ID 560686.1.

Disk group has used % of safely usable free space

OEM Alert Message looks like;

Message=Disk group DISGKGROUP_FLASH_01 has used 75.08% of safely usable free space. Metric=Disk Group Used % of Safely Usable Metric value=75.08 Disk Group Name=DISGKGROUP_FLASH_01 Severity=Warning Target Name=+ASM1_DBSRVR.siva.com Target type=Automatic Storage Management Host=dbsrvr.siva.com Occurred At=Sep 29, 2011 11:14:52 PM IST Acknowledged=No Notification Rule Name=DBSrvr ASM Health Check Notification Rule Owner=DBA

 

By default:
This metric will generate a warning alert if the Disk Group is using 90% of the Safely usable space and
Critical warning for 100 %. Threshold limit can be changed to generate alert at different values.

This metric is collected at a time interval of 15 minutes.

Metric Collection:
This metric is collected from the view V$ASM_DISKGROUP_STAT

Used % of Safely Usable = 100 - (usable_file_mb/usable_total_mb)*100 Where usable_total_mb = total_mb - required_mirror_free_mb)/redundancy_factor

total_mb and required_mirror_free_mb will come from the V$ASM_DISKGROUP_STAT  view column and

Redundancy Factor	Disk Group Type
1	External
2	Normal
3	High

Query:

select 100-(FREE_MB/TOTAL_MB)*100 as "Used % Safely Usable Area",  Name from v$asm_diskgroup_stat

Alternatively connect to ASM and check the free space;

ASMCMD> lsdg

Workaround:
If the Archive Log file occupies the ASM Disk group, move the files or delete files to free up Disk group.

Permanent Resolution:
New disks can be added in a disk group to avoid the alerts.
Go to the Disk Group general page ---> and click on add button to add a new disk to a disk group.

Steps to set database on flashback mode in RAC for Oracle 11g

 

---- Check if flashback on?

SELECT flashback_on, log_mode FROM v$database;

--- Check for Flashback Parameters existing

set linesize 121 col name format a30 col value format a30 SELECT name, value FROM gv$parameter WHERE name LIKE '%flashback%';

---- Stop the RAC Database , it will stop all the instances of the DB

srvctl stop database -d sfodb

--- Start the DB in mount state

srvctl start instance -d sfodb -i sfo38u1 -o mount

-- Set the Flashback on

alter database flashback on;

--- Open the database

alter database open;

--- Start the remaining instances of the RAC

srvctl start instance -d sfodb -i sfo38u2 -o mount exclusive

-- Verify the flashback settings

select INST_ID,Name, FLASHBACK_ON from gv$database;