backup:
svnadmin dump /path/to/repo | gzip -c > myBackup.gz
restore:
svnadmin load /path/to/repo < /path/to/dumpfile.dump
after restoring, don’t forget to set the rights accordingly (forgetting that will mark you as noob):
chown -R svn:www-data /path/to/repo chmod -R g+w /path/to/repo