ANSWER:

That command would serve its purpose but is there any reason you aren’t using any compression like gzip or bzip? Also since this is in a cron I see no real reason to have the -v flag, no need to see the output.

Just add a -z to your command flags for gzip.

So your final command would be:

tar -zcf /site_backup.tar.gz /public_html/

by Sean S from http://serverfault.com/questions/382467