Negative values and critical state when checking flash recovery area usage

[ccztux]

Sometimes, the flash recovery area usage checks, are exiting with state critical and negative usage values. This happens on several monitoring-/oracle-systems.

Example:

CRITICAL - flra (/u01/app/oracle/fast_recovery_area) usage is -2.80%

Please let me know, if i can provide some more helpful infos.

[mt-lmk]

Seems like Oracle sometimes returns some funky numbers and reclaimable space is bigger than used space. That causes the Flash recovery area usage to be negative.
Wed May 16 00:08:01 2018: fetchall_array:
SELECT
name, space_limit, space_used, space_reclaimable, number_of_files
FROM
v$recovery_file_dest

Wed May 16 00:08:01 2018: args: $VAR1 = [];

Wed May 16 00:08:01 2018: RESULT:
$VAR1 = [
[
'+DATA',
'85899345920',
'10230956032',
'16989028352',
'8'
]
];

[mt-lmk]

As for the critical returned in this case use --warning ~:90 --critical ~:95 which will allow the negative values.