Help me, help me, my logs are over-sized!

I have a lot of servers and only home-grown monitoring.  I needed a solution that would tell me if a log file started to grow outside of its normal size.  I listened carefully at PASS Summit on how I should “right-size” my log files and came back with a plan to tackle all of them. Fast-forward a few months and I am still having trouble even after sizing them to what I thought they should be. One of the problems is that my backup solution is “touchy” with log backups and awesome at getting the full ones. I built a report to watch for missing transaction log backups, which isn’t perfect yet.  I needed a more immediate solution and after getting another Disk Space Email Alert, I knew what I had to do.  Here it is, my Large Log File Alert.

CREATE PROCEDURE [dbo].[usp_LargeLogFileAlert]
 @LogThreshold int = 1024
AS
--This procedure sends out an alert message when a logfile has exceeded a set threshold.
--It can be scheduled to run daily so you can act quickly to resolve.

IF EXISTS (SELECT * FROM tempdb..sysobjects
WHERE id = object_id(N'[tempdb]..[#LargeLogFileAlert]'))
DROP TABLE #LargeLogFileAlert
CREATE TABLE #LargeLogFileAlert (
 DatabaseName VARCHAR(50) NOT NULL,
 LogMB INTEGER NOT NULL)

DECLARE @SizeMB INT
DECLARE @DatabaseName VARCHAR(50)
DECLARE @AlertMessage VARCHAR(500)
DECLARE @MailSubject VARCHAR(100)

/* Populate #LargeLogFileAlert with data */
INSERT INTO #LargeLogFileAlert
SELECT RTRIM(instance_name) AS DatabaseName, cntr_value/1024 AS SizeMB
FROM sys.dm_os_performance_counters
WHERE counter_name = 'Log File(s) Used Size (KB)'
AND instance_name != '_Total' AND cntr_value/1024 > @LogThreshold --Threshold in MB

DECLARE LogAlert CURSOR FAST_FORWARD FOR
SELECT DatabaseName, LogMB FROM #LargeLogFileAlert 

OPEN LogAlert
FETCH NEXT FROM LogAlert INTO @DatabaseName, @SizeMB

WHILE (@@FETCH_STATUS = 0)
BEGIN
SET @MailSubject = 'Log for ' + @DatabaseName + ' has exceeded threshold on ' + @@SERVERNAME
SET @AlertMessage = @DatabaseName + ' is ' + cast(@SizeMB AS VARCHAR) + ' MB. Please verify transaction log backups are working.'
-- Send out email
EXEC msdb..sp_send_dbmail @recipients = 'you@email.com',--Change to your email
@subject = @MailSubject,
@body = @AlertMessage
FETCH NEXT FROM LogAlert INTO @DatabaseName, @SizeMB
END
CLOSE LogAlert
DEALLOCATE LogAlert
DROP TABLE #LargeLogFileAlert

GO

The threshold is adjustable by server. I picked the one I did because my servers have a lot of small databases.

Next I tossed it into a SQL Agent Job and have it run once a day on each server. It is light so I am not worried about it causing performance issues. It will email me for each database that has a log file larger than the limit I set. It won’t email at all if there aren’t any. Once I get my logs sized properly, I can turn them off. I used my CMS to deploy the stored procedure and SQL Agent job to all my servers and Yay, I know more about my environment.

This is my first attempt at joining the blog party which is number 62 – hosted this time by Robert Pearl (@pearlknows), hopefully I did it right.

About andreaallred

SQL Server and helping people is my passion. If I can make someone laugh, I know I have made a difference.

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