Whichever type of repository you use, it is vitally important that you maintain regular backups, and that you verify the backup. If the server fails, you may be able to access a recent version of your files, but without the repository all your history is lost forever.

The simplest (but not recommended) way is just to copy the repository folder onto the backup medium. However, you have to be absolutely sure that no process is accessing the data. In this context, access means any access at all. A BDB repository is written to even when the operation only appears to require reading, such as getting status. If your repository is accessed at all during the copy, (web browser left open, WebSVN, etc.) the backup will be worthless.

The recommended method is to run

svnadmin hotcopy path/to/repository path/to/backup --clean-logs

to create a copy of your repository in a safe manner. Then backup the copy. The --clean-logs option is not required, but removes any redundant log files when you backup a BDB repository, which may save some space.

The svnadmin tool is installed automatically when you install the Subversion command line client. If you are installing the command line tools on a Windows PC, the best way is to download the Windows installer version. It is compressed more efficiently than the .zip version, so the download is smaller, and it takes care of setting the paths for you. You can download the latest version of the Subversion command line client from the Subversion website.