sqlserver logfile_usage Value - Explanation from IM Value
Release : 9.0.2
sqlserver probe any version
SQLServer 2012 or above
Component : UIM - SQLSERVER
In the SQL Server probe value field in the status give the free_pct (Log Space free percentage) which is QOS_METRIC value but the customer is comparing the data with used_pct (Log Space used percentage). That's the reason the data are not matching
DB value given by probe is 82.27% (Log space free percentage) means used percentgae = (100 - 82.27) % = 17.73% (which same value based on the output).
The same way customer can match the data for all the databases.
But the if need to change the QOS_METRIC from free_pct to used_pct
To verify the unlimited transaction log file run the below query if the unlimited = 1 then the probe will return the free_space = 100%
select ''?'' db_name, (select CAST((total_log_size_in_bytes / 1048576.0) AS DECIMAL(10,2)) from [?].sys.dm_db_log_space_usage) allocated, (select CAST((used_log_space_in_bytes/1048576.0) AS DECIMAL(10,2)) from [?].sys.dm_db_log_space_usage) used, (select CAST(used_log_space_in_percent AS DECIMAL(10,2)) from [?].sys.dm_db_log_space_usage) used_pct, (select count(*) from [?].sys.database_files cg where state_desc != ''RESTORING'' and max_size = -1 and type = 1 and growth > 0) unlimited