I’ve just setup a very simple backup system that works over FTP. Windows only I’m afraid but i’m sure the equivilent isn’t too hard on other platforms.

Tools
Firstly I used two very simple free/open source command line tools:
SSLFTP – simple FTP tool that works in passive mode or over secure connections.
and
7-zip – an open source zip file archiver.

Download and install the above on the machine you wish to backup from.

FTP Script
I then wrote the following script file to handle the FTP (saved as ftpscript.txt):

open ftpusername:ftppassword@ftp.host.address
del backup7.zip
rename backup6.zip backup7.zip
rename backup5.zip backup6.zip
rename backup4.zip backup5.zip
rename backup3.zip backup4.zip
rename backup2.zip backup3.zip
rename backup.zip backup2.zip
put c:\backupscripts\backup.zip
bye

All this is doing is taking a copy of seven days worth of backups and deleting the oldest then uploading the newest backup.

Backup Script
To decrease the time taken to FTP everything I use the following batch file to keep three days worth of backups locally, zip the files I want to backup and call the above FTP script (saved as daily.bat):

delete backup3.zip
rename backup2.zip backup3.zip
rename backup.zip backup2.zip
7z a -tzip d:\backupscripts\backup.zip d:\inetpub\wwwroot\
7z a -tzip d:\backupscripts\backup.zip d:\DB_Backup\
7z a -tzip d:\backupscripts\backup.zip d:\other_folders_to_keep\
sslftp -run ftpscript.txt

The 7z lines mean the following:
7z – execute the 7-zip exe
a – add files
-tzip – archive file type of zip
d:\backupscripts\backup.zip – archive to add to (will create if does not exist)
d:\backupscripts\backup.zip d:\other_folders_to_keep\ folder/files to add to archive

And thats it! All you do then is setup a scheduled task (Start, Settings, Control Panel, Scheduled Tasks) to run every night and you’re done!

What no FTP?
If you don’t have any FTP space you can backup across a network/internet connection and setup a PC as an FTP server using the excellent FileZilla.

UPDATE: see comments for some notes from William who suggests some alternative syntax if you have issues with the above and a more logical sequence to protect against things going wrong mid-process.