As a database professional, I get asked to review the health of database environments very often. When I perform these reviews, one of the many checks I perform is reviewing backup history and making sure that the backup plans in place meet the requirements and service level agreements for the business. I have found a number of backup strategies implemented using full, differential and transaction log backups in some fashion.

In more cases then I would like to share, I have found business critical databases that are not being backed up properly. This could be in the worst case having no backups or a backup strategy that does not meet the recoverability requirement of the business.

When doing an initial check I gather many details about the environment. Regarding backups, I capture things such as recovery model, last full backup, last differential, and the last two transaction log backups. Having this information will allow me to determine what the backup strategy is and point out any recover-ability gaps.

Some examples I have found are 1) no backup’s period, 2) full backup from months ago and daily differentials. In this case the full had been purged from the system, 3) Full backup of user database in Full recovery mode with no transaction log backups, 4) Proper use of weekly full, daily differential, and schedule transaction log backups – however the schedule was set to hourly and the customer expected they would have no more than 15 minutes of data loss.  I am happy to report that I do find proper backup routines that meet the customers’ service level agreement too.

The code I like to use for this check is below.

SELECT
  DISTINCT
        a.Name AS DatabaseName ,
        CONVERT(SYSNAME, DATABASEPROPERTYEX(a.name, 'Recovery')) RecoveryModel ,
        COALESCE(( SELECT   CONVERT(VARCHAR(12), MAX(backup_finish_date), 101)
                   FROM     msdb.dbo.backupset
                   WHERE    database_name = a.name
                            AND type = 'd'
                            AND is_copy_only = '0'
                 ), 'No Full') AS 'Full' ,
        COALESCE(( SELECT   CONVERT(VARCHAR(12), MAX(backup_finish_date), 101)
                   FROM     msdb.dbo.backupset
                   WHERE    database_name = a.name
                            AND type = 'i'
                            AND is_copy_only = '0'
                 ), 'No Diff') AS 'Diff' ,
        COALESCE(( SELECT   CONVERT(VARCHAR(20), MAX(backup_finish_date), 120)
                   FROM     msdb.dbo.backupset
                   WHERE    database_name = a.name
                            AND type = 'l'
                 ), 'No Log') AS 'LastLog' ,
        COALESCE(( SELECT   CONVERT(VARCHAR(20), backup_finish_date, 120)
                   FROM     ( SELECT    ROW_NUMBER() OVER ( ORDER BY backup_finish_date DESC ) AS 'rownum' ,
                                        backup_finish_date
                              FROM      msdb.dbo.backupset
                              WHERE     database_name = a.name
                                        AND type = 'l'
                            ) withrownum
                   WHERE    rownum = 2
                 ), 'No Log') AS 'LastLog2'
FROM    sys.databases a
        LEFT OUTER JOIN msdb.dbo.backupset b ON b.database_name = a.name
WHERE   a.name <> 'tempdb'
        AND a.state_desc = 'online'
GROUP BY a.Name ,
        a.compatibility_level
ORDER BY a.name

Ensuring that you have backups is crucial to any check of a SQL Server instance. In addition to ensuring that backups are being created, validation of those backups is just as important. Backups are only valid if you can restore them.

When I have the opportunity to share my experiences of backup and recovery with people I always like to share about how to backup the tail end of a transaction log and how to attach a transaction log from one database to another in order to backup the tail end of the log. I have created a couple of videos on how to accomplish this that you can view using this like http://www.timradney.com/taillogrestore