SVN repository backup strategies
We use svnadmin hotcopy, e.g.:
svnadmin hotcopy C:\svn\repo D:\backups\svn\repo
As per the book:
You can run this command at any time and make a safe copy of the repository, regardless of whether other processes are using the repository.
You can of course ZIP (preferably 7-Zip) the backup copy. IMHO It's the most straightforward of the backup options: in case of disaster there's little to do other than unzip it back into position.
There's a hotbackup.py script available on the Subversion web site that's quite handy for automating backups.
http://svn.apache.org/repos/asf/subversion/trunk/tools/backup/hot-backup.py.in