So I need to backup the SQL DB of a mission critical app. The app sits on a virtual machine and backups need to get written to a NAS device. But if there is a network or NAS issue then the backups won't get written, so no current backups. What I do in this scenario is write the backups locally first, to c:\DB_backups, then script a task to sync the backup directory to the NAS. If I have daily backups then the NAS will store all of the daily rolling backups, but that will eat up space on the C drive, which is bad. So I need to purge the DB_backups folder, there are a few ways to do this and the easiest I found is to use powershell:
Get-ChildItem 'C:\DB_Backup' -Recurse | Where {$_.creationtime -lt (Get-Date).AddDays(-10)} | Remove-Item
This is pretty clever on powershell's part, lets step through what it does.
Get-ChildItem 'C:\DB_Backup' -Recurse
What this does is list all of the items in this folder as objects, and I am recursing through all of the folders in this folder, but that is not necessarily needed for this job.
Where {$_.creationtime -lt (Get-Date).AddDays(-10)}
The objects in this folder is then
piped to this line.
Where is an alias for
Where-Object. We are using
where because we only want to select files with specific attributes from this directory. These attributes are defined by the
$_.creationtime. The creation time is then compared to today's date (
Get-Date) using
-lt (less than). But we only want the files older than 10 days ago, so we subtract 10 from
Get-Date, using the
AddDays modifier. So now we are listing all of the files older than 10 days, pretty neat, now to delete them.
Remove-Item
The cmd way of doing things is using
del, which is actually an alias for -Remove-Item, neat. This will remove the 10 day old objects we piped to it in the previous line.
Save it all as a .ps1 file and
schedule the job in task scheduler to run daily to keep your C drive to size.
