Using the FORFILES Command to Delete SQL Server Backups
Recently I constructed a new backup process that I want to institute globally across all my SQL Server 2005 instances. This backup process will not only backup all the databases I point it towards, but at the same time will script out the backup commands to a single file in the format of F_YYYYMMDD.sql if the backup process is a full database backup or D|T_YYMMDD_HHMMSS.sql if the backup process is a differential (D) or transaction log (T) backup. These script files are then stored in a subfolder under the backup directory on the SQL Server. The process works great, but I only don't want to keep every .sql file. I cant see the need to keep these scripts after 30 days. Is there a way I can automate a file deletion process from within SQL Server?
While there are many ways the file deletion process can be handled with T-SQL code. I use the xp_cmdshell command along with the FORFILES command for a very similar process to what you have outlined. Solid information of FORFILES is available from Microsoft TechNet, but I will touch on much of the structure and use of FORFILES for your purposes in this tip.
The FORFILES command will select a subset of files and execute a command against the set. The command requires the following parameters and accepts the following variables:
|/m||Search Mask (default is *.*)|
|/s||Subdirectories will be searched recursively if this parameter is included|
|/c <command>||Command to be executed against each file in the result set, commands must be enclosed in double-quotes, default is "cmd c/ echo @file"|
|/d||Date range for file selection, using Last Modified Date as the criterion for the file. When the /d parameter is in the form of MM/DD/YYYY, file meeting the criteria of +/- the specified date are included. When in the format of a smallint (-32,768 - 32,768) the files +/- the files with a modified date +/- that number of days from the current date are included in the file result set.|
|@FNAME||File name without extension|
|@PATH||Full path of the file|
|@RELPATH||Relative path of the file|
|@ISDIR||Evaluates as TRUE if the file type is a directory|
|@FSIZE||File size in bytes|
|@FDATE||Last modified date stamp on the file|
|@FTIME||Last modified timestamp on the file|
Using these parameters the following examples could be constructed to take care of your dilemma for deleting your backup script files. You can create scripts based upon modification date/time or backup type. You can even construct scripts that utilize both criteria. We will now take a closer look at these potential scripts. Remember that you will be executing these from within T-SQL code, so you will need to wrap the statements within an xp_cmdshell call in the format of EXEC xp_cmdshell 'FORFILES COMMAND'. Please note that in all examples I am using the /Q and /F flags for the del command. These signify that the command will use quiet mode (/Q) and will even delete read-only files (/F).
Delete all .sql files in the C:\Backup directory and its subfolders where the file modified date is older than 10/18/2008.
|EXEC xp_cmdshell 'FORFILES /p c:\BACKUP /s /m *.sql /d 10/18/2008 /c "CMD /C del /Q /F @FILE"'|
Delete all .sql files in the C:\Backup directory and its subfolders where the file modified date is more than 30 days old.
|EXEC xp_cmdshell 'FORFILES /p c:\BACKUP /s /m *.sql /d -30 /c "CMD /C del /Q /F @FILE"'|
Delete all .sql files in the C:\Backup directory and its subfolders where the file modified date is more than 30 days old and the file name starts with an "F_".
|EXEC xp_cmdshell 'FORFILES /p c:\BACKUP /s /m F_*.sql /d -30 /c "CMD /C del /Q /F @FILE"'|
- Modify the code above to fit your retention policy, file structure and needs.
- Add the modified code to a subsequent job step in the SQL Agent job that runs your backup process. Include verbose SQL Agent job logging to verify that the process is working correctly.
- Keep in mind that the FORFILES command does a lot more than just deleting files. As an example, it can be used to list files for other processes as well.
- Review other file deletion automation tips from MSSQLTips.com.
- Review tips on xp_cmdshell at MSSQLTips.com
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